WN can "want" to attract business customers. IMO, they catering to a small portion of the business clientele. A majority of the serious business travelers are going to care about all the amenities like lounges, premium cabin, upgrades, etc. The fact they push SWABIZ so hard is laughable.
What's a "serious business traveller"? You either travel on a business trip(s), or you don't.
I would drop the "business" part, either you're a serious traveller or you're not, the reason for travel is probably less of an issue. Outside of here, there just aren't very many non-business serious travellers. But there are certainly many non-serious business travellers, and even more non-serious non-business travellers.
I would say I am a serious traveller (being on this site should make that obvious), but only travel for business about every other month (pre-covid). But I have colleagues that travel weekly, and some love Southwest for all their travel and others only fly UA or AA or DL (usually depending on which hub they live by). The ones that fly UA/AA/DL, like me they show up early to use the lounge, they will fly a little extra to keep their status, they have the credit card, they fly the family to FL through ATL for the miles. The ones that fly WN, want to spend the least amount of time at the airport as possible, the flight is just the way to get where they are going.
Nothing wrong with either, just personal preferences.
I think Southwest's challenge, or hope based on the statements from leadership, is that those serious travellers who will pay extra to fly UA/AA/DL will pay extra to fly Southwest. The reason that is hard or unlikely, is that Southwest doesn't offer the benefits that are worth that extra cost. To put it another way WN would love the revenue of that business traveller who flies first class every week, but why would that business traveller who flies every week give up first class?
Personally I grew up in an airport where we always had a connection and being a pilot and loving aviation, I love connections (two flights for the price of one). I rarely fly southwest because its always a 737 and usually nonstop. I fly DL because of the product and consistency, the aircraft variety and connections is a nice benefit.
It also hurts WN that they don't fly to my most common destination MSN.
One mile of highway gets you one mile, one mile of runway gets you anywhere.