Kind of depends what you are getting paid, but if it is less then $100k say, you can easily find remote jobs that pay more, play them off against each other. The companies are using sharp business practice to get you as cheap as possible, you can do the same to get as much as possible. Apply for 100 remote jobs, interview, smash the interviews, ask for top $ from all of them.

See https://remoteok.com/, etc.

If on he other hand, you are paid $200k and the colleagues are being paid $400k ... well you are well paid, might be harder to get a fully remote pay rise, but not impossible I think.

Now lets say you are paid $50k for argument sake, and you talk to your boss saying you want $100k and you can get that elsewhere. They would be crazy to let you go as $100k is still probably less than they are paying in the US if you are doing the same job.

What I have learned is the 'policy' evaporates under enough pressure. Of course they may still say no, in which case look around.

If they are paying you less than you are worth, they are not your friend, don't feel bad about moving to another job immediately.