Giant companies making money hand over fist pay a lot of "don't fuck this up" salaries. The primary goal for everyone is to keep the money printer running smoothly; everything else is secondary.
When everyone is quietly pretending you’re not a fireman but you are it leads do a disconnect where everyone is playing charades.
Firefighters who also do development work to reduce fires and make their firefighting easier.
That said developers also do firefighting. They can be an escalation point for deeper system issues that may elude SREs.
Maybe this is okay for a late stage company that is in the value extraction mode. In that case the private equity playbook is to lay off the app developers, and they can throw more money at ops to increase efficiency of the shrinking pie.
On the other hand if you're in a highly competitive growth industry then you need to innovate, and if you optimize for SRE talent, you won't have sufficiently senior engineering talent to find the right balance between innovation and stability.