There is no evidence that employers have been trying to keep pace. There is ample evidence that they have tried to suppress wages.
For decades what they are calling 'keeping pace' has been performed by knocking the legs out of their employees.
Yes, there are individual entrepreneurs who try to be "the good guys". But they're operating at a competive disadvantage and usually can only afford to do so for a limited time due to e.g. strong initial funding. If you want corporations to behave this way you don't want corporations, you want co-operatives where all workers are also owners of the company because this completely removes the dynamics caused by the conflict between the interests of the shareholders/owners and those of the employees/workers by turning both into the same group.
I think it's a perfectly legitimate political opinion to think that business owners should be allowed to roam freely and pursue profit over worker well-being, but I'd expect people who hold this opinion to at least be honest about it and not pretend employers are altruistic humanitarians.
Founding a co-op arguably avoids some of that but as you correctly point out there is little incentive to do business with co-ops if you have to (or want to) act optimally within the system (which depending on your resource constraints can mean "being able to feed yourself and continuing to have a roof over your head"). This is why co-ops are somewhat incestuous: there are for example marketing co-ops which primarily do marketing for other co-ops, which in turn prefer paying co-ops to do their marketing, because they're all in the same boat. Alternatively many co-ops target the public sector or municipal governments as they're less profit-focussed and instead often hire for things co-ops can more easily guarantee (e.g. avoiding child labor in supply chains, "green energy", various sustainability metrics etc).
You can't outcompete unethical businesses when being ethical is a competitive disadvantage. No matter how many regulations we bolt onto it, the system will always reward those companies that try to game them rather than those that genuinely believe in their stated ethical goals. Of course that doesn't mean the regulations are pointless: often trying to do the bare minimum yields better externalities than not doing anything at all.