I guess firefighting is the right metaphor, to fixing big errors in live production environments: it takes a different skill and mindset, to do things under pressure, nothing wrong to praise that.

But I think it is wrong, to talk down the job of actual firefighters, because:

"Clearly there are companies praising heroic fixes, while not praising too much regular maintenance"

that is a seperate issue.

the fire metaphor still works: we have arsonists (that build up tech debt or just bad practices) that turn firefighters (by fixing in emergency mode).

Of course not all tech debt is bad, the trick is know when to use it to good effect, not building it up everywhere only to pay it back at the costliest moment. It's all a balancing act.