Like you say, the set of people who'd be pushing the argument from that angle is inherently pretty small. Basically either those that don't need money from a job in the first place + those that want some extra money from a job but only when it's extremely convenient and that boundary just happens to be WFH or not.
The others don't inherently care more about their employer than themselves, they care more more about the money impact it means for their compensation. More efficient = more valuable to employer = more compensation. For employees benefit only = less valuable to employer = less compensation.
My labour history knowledge is pretty non-existent, but I assume past progress was often made via unions, e.g. 8-hour work day. Seems like this is a situation begging for workers (at Amazon and elsewhere) to unionise and demand the right to WFH through the power of collective bargaining.
The workers that progressed labour rights in the past surely mostly needed their jobs too, so this situation doesn't seem unique at all.
Legal progress yes, but it had plenty of loopholes and pushback and wasn't normalized until the Ford Motor Company did it (combined with going from a 6-day work week to 5 days), because Henry Ford believed the extra downtime would increase productivity and possibly even demand for the cars he sold. His success compared to competitors is why everyone else followed suit.
(I want to preface this that I consider myself pro-union, so people don't just stop reading halfway through. Also this is all my 2 cents, I'm not an expert in these topics by any means)
Unions can definitely solve it, be it the actual optimal thing to do for each individual or not, should everyone involved unionize. Even then though, workers would also like to work 2 hours a week for the same pay... it doesn't mean a union forming to do it would be successful. The same dynamics eventually come back into play: is it actually more efficient? If not, is that money loss something the union workers are willing to take? It's tempting to say "they can just force the business to cut profits anyways!" and... sure, they could, but they could do that while being more efficient and get even more money too. I.e. ultimately the union and people that make it up are just as interested in making sure they balance doing a certain amount of what they don't like with a certain amount of being efficient to get the most out of it. Whoever you make the group that needs to be convinced it's worthwhile you still need to convince it's the overall more efficient choice.
On the topic of unions though, unions typically form for lower paid workers. Not that they never form for higher paid workers but they tend to have more options already, less to gain, and more to lose when joining a union compared to a lower paid workers. The amount of effort a business will put in to avoiding a union will also vary with pay as the relative asks tend to scale as well e.g. on pay a union for ~70k/year auto workers wanting a 10% pay bump is cheaper to accept than a union for ~140k/year tech workers wanting a 10% pay bump.
I think tech workers will eventually make and join unions regularly. Maybe not in the current pay and political climate, but eventually. Until then our relatively small problems of "having to deal with showing up in person at work for one of the higher paying jobs" are not going to be as huge of drivers to unionize as places that wanted to keep fingers or earn a more average salary.
They don’t make labor law like they used to, unfortunately. The Supreme Court has steadily been gutting it for 40+ years now, and unionism has unfortunately been subsumed into culture war politics so that even a bare acknowledgement of the imbalances in negotiating power between management and labor is impossible without getting entangled in tribal-political ideology. Which means there’s equally no hope that Congress will reverse any of the erosion of labor rights inflicted by the courts.
The others don't inherently care more about their employer than themselves, they care more more about the money impact it means for their compensation. More efficient = more valuable to employer = more compensation. For employees benefit only = less valuable to employer = less compensation.