I'm between junior and medior right now.

This might be egotistical so take it with a grain of salt, but I've started realizing that there's no compensation for me anymore if I do well. Tldr the company im working for has a lot of gaps I could put effort in and make it perform well, but it's not my company, so I don't.

Why would I? what's in it for me? Will I stay there after 5 years?

This isn't even limited to me. I talk to colleagues that could improve our current position if they were being put on the issues at hand. They're not being utilized, so they just do whatever.

Companies expect us to do this proactively, because we're such good workers.

I've done my fair share of overworking myself for a company that ditched me once I'm burnt out. It's kind of like ego-death, but for validation. You realize that all this effort is futile. The company grew, you didn't. In one year all the higher-ups have a fancier title and you're still the dev.