Earlier quoted context omitted.
This is really important. At my first job, in 2010 or so, we were using Servlets. Not just Servlets, but Servlets with some home-rolled shims to make it act like Servlets 1.0 in a distinctly post-1.0 world. Doing pretty much anything in there was slow, and I realized it at the time. So during a hack week I built an MVC layer on top, with routing that didn't involve XML files and just--made it generally better . Or so…
Where do you think your understanding went wrong initially? You said you realized that doing anything in the old system was slow. Was it not actually slow? Was the slowness not relevant because there weren't actually that many routes? Were your coworkers resigned to having some minimum level of tedium in web development? Or something else?
The problem I hadn't fully understood was a mix of the last point you suggested--tedium's just how it is--and a set of libraries built up as coping mechanisms that were intrinsically tied to the servlets process. Not really written to be able to be shimmed into a better world without dragging the whole thing there, and not enough appetite to try for it.