Will Austin get all those route? I don't think so. But I would not be surprised by AMS, CDG or NRT in the slightest. China and Ireland seem unlikely IMO
I mean tbh, that's not really saying much. I fly out of TPA frequently and Tampa is considerably smaller than AUS but even TPA already AMS and CDG with DUB right around the corner. Yeah NRT-TPA isn't happening anytime soon but that has more to do with range issues of transpacific flying to the southeast in general. Meanwhile MCO about an hour east of Tampa has a nonstop to DXB and bucketloads of other TATL flights, all the while NH/JL have been seriously floated interest in starting NRT-MCO if it weren't for the lack of an aircraft that could make the flight. Austin's population is roughly twice Tampa and Orlando combined but has substantially less flights than either.
The problem with Austin really has nothing to do with the city itself. It has more to do with Texas. AA and UA have a vested interest in keeping AUS as small as possible because it is an important captive market for them. They can effectively do this with little to no effort by dumping massive amounts of capacity to IAH and DFW. The proximity of not 1 but 2 superhubs within 40min of AUS by air really kills its ability to stand alone regardless of how good Austin's star power when you're competing with Houston and Dallas. Austin is a very fast growing city, and anywhere outside of Texas, it could easily stand alone as its own hub attracting that kind of international traffic but unfortunately it's not. Living in the shadow of giants is tough. Ask any airport within in the shadow of ATL (Georgia), ORD (Illinois), DEN (Colorado), or LAX (SoCal besides SAN) how hard it is to compete with the big boys and you can start to understand AUS's predicament by being sandwiched between two of those in the Texas triangle.
Don't get me wrong, I have no doubt that AUS will get the likes of NRT, PVG, etc. at the rate it's growing. But it will take a lot longer than if IAH and DFW weren't right next door, when you consider cities on a similar trajectory to Austin like Seattle have had their Int'l air service essentially quadruple overnight relative to AUS. In Seattle's case, part of that has to do with the benefit of geographic isolation unlike Austin, but also that DL has made a somewhat significant, if not misguided effort to build up SEA in a way that they're not doing at AUS, at least not yet. For AUS to start seeing some seeing some dividends, they have to follow the SEA model and figure out how to get DL to build up something beyond just another focus city on their inflight magazine. AUS would well aware that any kind of major build up there from a carrier like DL is going to be watched very carefully from managers with raised eyebrows in DFW and IAH and that any sudden or aggressive changes could trigger a vicious counter response from AA and UA. One could argue that DL trying to compete in Texas is almost as difficult as trying to build a hub in ORD given how short the distance is between AA and UA's fortress hubs and AUS and the amount of capacity they could dump together to force DL out much like in ORD. For DL to succeed in AUS, they'll have to make some drastic changes and abandon the tepid approach they're taking now which would inevitably mean facing AA and UA head on instead of pretending to ignore them. For now, I doubt they can pull that off considering how they're getting their ass handed to them by B6 in BOS and AS in SEA. If DL wants to get in on the action in Texas, AA and UA aren't going to let it capture AUS, one of their most valuable captive markets, lying down so you can definitely expect a fight when that day comes.
In a way, the IAH/DFW/AUS dynamic is kind of like a bigger variant of the SF Bay Area. You have SFO/OAK/SJC with SFO and to some extent OAK as hubs that dominate the area and then SJC as the "other" airport that lies in the shadow of the first two and is used by a very specific group of people that are going to that part of the Bay. AUS and SJC both share this weird dynamic of the business tech crowd that possibly to the detriment of those airports is so niche that instead of eating away at the more diversified share of the bigger airports, caters exclusively to this unique biz tech crowd that puts it on a shaky foundation of thin ice which is especially prominent with SJC and to some degree AUS when anything in the tech economy takes a hit, highlighting the risks of putting all your eggs in one basket. This is the basic reason why airports like TPA have more service than AUS despite being significantly smaller, as essentially what it comes down to is how diversified the economy is. A general rule of thumb is that a smaller, more steady, and diversified economy is more sustainable in the long-term than a larger but more unpredictable one where longevity is the most important thing for airlines when starting routes. Austin blows the doors off Tampa in the startup/entrepreneur scene which everybody touts, but that crowd is not reliable enough for an airline looking to start a route, so that argument actually works against AUS and in favor of TPA which focuses more on promoting a reliable corporate presence to airlines in addition to the already consistent flow of tourism. Consistency is the key here. Unicorns like those found in Silicon Valley are notorious for nosediving and that has exposed some of the potential problems under the SJC model with cutbacks resulting directly from the performance of the tech industry and little else to fall back on. AUS should understand that dynamic carefully and take caution to avoid replicating it. I should add one other thing that unlike AUS in Texas, TPA and MCO despite being so close don't compete for connections nor does either airport have a hub carrier which is the complete opposite of the Texas situation where IAH and DFW are an issue for AUS precisely because they have strong hub carriers with numerous connections to AUS. MIA connections don't dominate any airport in FL anywhere near as much as the Texas duopoly does in AUS.
Austin will grow as will its airport given the exploding population and number of Fortune 500 companies opening up shop in the city but that also means that it will have to learn to hold its own against Dallas and Houston before it can really takeoff. Watch this space.