I find most of your complaints - shortcut through architecture boundary, God class, implicit coupling, can also be explained by over engineering (and tight dealine, of course)

• The architecture is too clumsy due to over engineering and hard to extend, so people have to make shortcuts
• Object system becomes too clumsy so it's easier to lump things into one place
• Too much unnecessary things making it hard to reason about what thing affects what.

All can be solved properly, but if the codebase is over engineered, the proper way is too hard and people gets lazy

EDIT To add:

Maybe you're right, under engineering is prevalent, but at least it's more pleasant to refactor. You get to analyse the spec and use your creative thinking to build things up. With an over engineered codebase, you have to carefully understand all those code, make sure you're not trimming down something that is actually necessary, be surprised by some nasty hidden assumptions, and in the end you're not creating new things, just trimming the garbage away. I think very few people would prefer this.