But we caused that.
If you look at the 90s + 00s, everything was moving towards unified systems, things like small talk, winforms, spring, asp.net, etc. were moving everything into the IDE, you used one language, one framework, one build system. Then people started adding javascript, but even that was getting semi-unified as people coalesced on jQuery, jQueryUI, etc.
Then something happened in the late 00s/10s, and suddenly we had SPAs and noSQL, then microservices, then k8s and now we're here, in what is a mish-mash of 10/20 different systems with 10/20 different attack surfaces.
As my own off-the-cuff guess of what happened, I think perhaps people tried to apply the Unix philosophy, but without a central committee keeping everything aligned it's really not worked.
Serving an interactive page that stores data over sessions should be a trivial solved problem at this point, and instead we've somehow made it where often the scaffold is vastly more complicated than the actual business logic.
Money. SaaS as a model allowed the service provider to take 100% control over the product and how it may or may not be used. Everything else is downstream from that.
FLOSS killed market for end-device software. Cloud+SaaS neutered FLOSS (the code is running literally out of your reach, so may as well be open and free, for any good that'll do you).
And this does actually connect to the security discussion, because despite the apparent belief that "security" is an unqualified good, it is actually just a mechanism of control, and whether or not it is good for you, depends on who is doing the protecting, and who are they protecting from. Very often these days, that threat actor is you.
Perhaps it would be helpful in these discussions if people mentally swapped "cybersecurity" for "police" or "military" or "humor of bureaucrats with power over you" - then it would be more obvious just how important it is to distinguish when you're being secured vs. you're being secured from, vs. accidentally finding yourself in the gears of the security aparattus.