That doesn't mean the 757 is dead.
Interesting, what they should do with the 757..
They can't do anything with the 757, because all of the tooling to build it has been destroyed. It was built at Renton, not Paine Field like the 767.
patrickjp93 & danipawa. I like your opinion of "what if" the 757 was still and option; and largely agree If....
I'd like to provide a more complete answer as to why it is not than just that the main tooling was destroyed (as it could be recreated if everything else was in place).
Restarting production of a 757 type aircraft would require much more than just building a new set of tooling. You would first have to convert all the drawings from mylar (paper original Final drawings died before the 757 was designed). Most companies cannot work from actual "blueprints" anymore. You need to have CAD controlled items - which means CAD drawings. Boeing found out how much of challenge and mess converting drawings were for the 747-8; and they have had to digitize a lot of prints related to the 737 and modern versions of the 767. This is a massive project.
Boeing (and the CAD community) already went through the pain of automating this before. That being said, it isn't necessary. Start from the basic specs of length, fuselage radius, wing box length, and then otherwise start fresh (and then grandfather it under the old type rating). The 757 is a 70s design. There's so much room to improve it you may as well just start fresh in terms of thought where possible. In fact, welcome to how the 777X was designed!
Since virtually all major part production has been shut down and the tooling destroyed (even at the sub contractor level); its better to design many new parts than to try to recreate the older parts. Most of the subcontractors who supplied the parts are actually not interested in going back to doing things the old way or producing the old version of current things they make for the aircraft industry.
There will by it's very nature of how the industry and parts suppliers have changed - require a lot of modernization work with the relevant certifications.
EASA and FAA allow new iterations of parts all the time. While there would be "many" in this case all at once, that's not nearly the problem you make it out to be. "Yeah, you remember how you approved those narrower, lighter, carbon-fiber cables for the 737 NG and they've proven to be amazing? Yeah we're replacing the old steel 757 cables with those. Approve please? K, thanks!"
A reality, is that you would likely cost at least 50%, and perhaps 75%, of a clean sheet design to pull this off, and return to market would not be much faster than a clean sheet program as well.
Speed is all a matter of FAA bandwidth in this case. All Boeing has to do is "Keep It Simple Stupid" on upgrading the designs. Don't try to shoot the moon. Put the fuselage ribs no farther apart than on the 737 MAX, make the fuselage out of Al-Li since we know it's lighter and stronger than the original alloy for the 757, sculpt out the inside for passenger comfort, extend the landing gear as far as needed so the new engines don't have to be mounted forward, use the proven lightweight components from other current assembly lines (wiring, tubing, cables, fasteners, etc.), and you don't create any pitfalls for yourself!
There is not enough of a market to justify that cost.
Of course... IF... IF it was still in production and all the old parts and equipment pieces still available... It would be a lot less costly and faster to modify and bring to market in a modern format.
Sometimes reality hurts.... The 757 is dead, and not coming back.
Have a great day,
The MOM has room for what, 800 planes was Boeing's last figure? That's plenty of market.