Have you seen Facebook's code quality? Have you seen any-big Chinese corpo code? There are a lot of very profitable businesses in the world with endless amount of tech debt. But tech debt is not necessarily a big deal in most scenarios. Obviously I'm not talking about mission critical software, but for general consumer/business software, it's fine. The hard part is understanding where you can cut the costs / add debt, and that comes from requirement gathering.

Riot Games around 2014(?) had the most profitable (non-mobile?) game in the world with an infamously horrific codebase, even by game standards.

At Microsoft this totally depends on the org and team. I've seen the full spectrum of quality here.

I'm pretty sure that Google is an advertising company that just happens to write software.