It's probably a real pain in the ass to fix - with some dumb tech debt reasons why. But, what's probably contributing the most to it is how Google incentivizes

It's probably a real pain in the ass to fix - with some dumb tech debt reasons why. But, what's probably contributing the most to it is how Google incentivizes people internally. The promotion process is tied very heavily towards launching new features. Maintaining existing products is (often) a bit of a career dead end for Googlers. It's safer to chase some new and shiny feature.