Rarely do companies and startups have the luxury to just lean back and take their time. It's a race against competitors, and everyone wants the advantage of being first.
I don't blame the devs, as much as I blame the market. People start taking shortcuts when they're judged by how fast they can crank out codes, and whether they can finish their sprints on time. You develop a culture of constantly putting out fires.
Hell, for some consulting firms this is a profitable business model: Deliver a partially working product, then spend 10-15 years on patching it up, on your clients bill.
Try verifying the correctness of a JavaScript program with model checking. It won't work. Or try verifying correctness with abstract interpretation. For any sound system the output will just be "Top".
We have very deliberately developed technologies that enable rapid development. For "make it so a little message appears on the screen saying what day it is" features this works very well but it means even our formal analysis methods fall over on dynamic languages with heavy framework use.
This isn't just laziness. I'm a hardcore PL person and even I think that soundness is largely a mistake when making real analysis engines.
Everything has to be "easy", so anyone can understand from a basic level.
It's one of the reasons we don't like verifying software using TLA, coq(proofs for programs), refinement types or using functional programming techniques. "It's too difficult for the average programmer".
The first excuse is that we don't have enough time to do things "right". When I get the metrics in how much time we waste fixing bugs after the fact, then it moves on the too difficult argument.
The result is we have an entire ecosystem full of buggy unreliable software.