Problem is that most big companies have "professional" management. And professional management is stuck in completely outdated command and control thinking even today. Whether its people taught by other people at other big companies or freshly minted MBAs none of them really seem to learn or know how to really govern, create autonomy, etc. etc. and there is very little incetive to.When you get the odd curious one they go and find agile, and the first thing they run into is SAFE, LESS and similar, which is the same old taylorism wearing the fresh skin of agile on top like a horrible costume.

"Support" is usually a different org, may be outsourced, may be centered in a different country.

The userbase is different, in a small saas company you will probably get fairly "high signal" complaints, this is not true for mass market products.

Fixing bugs is different, sometimes you need to cross 3 teams in different timezones and have a bunch of meetings to fix a bug. Often the real problem is that a business process or a legacy system is messed up and an individual dev is not going to have the political "swing" to be able to do anything about it.

Big companies are typically structured to limit the agency of ICs.

They will learn the deployment system some principal engineer in another organization set up is terrible, and will be powerless to fix it in any way.