If you think this is illegitimate wage discrimination I have a question for you, if you order coffee in bumfuck idaho, do you pay the barrista, who does the same work as one in Palo Alto, the same price for their coffee?
This is not a valid analogy. There are two decisions
1. Do I pay the price asked?
If I'm in Idaho and I want coffee and they are asking for Bay Area Starbucks prices the answer is "Yes." But that's because I'm used to it, and its not the point. The question is:
2. If the store buys a machine that decreases their costs by 20% am I entitled to demand a lower price?
Entitlement has nothing to do with it. If there is a machine that lowers the costs of production by 20% the price will drop, because there's now an opportunity for competition to drive down the cost of coffee. That's how things become more affordable in a market economy.
And this is the actual point of the analogy. When people can suddenly work from locations that have lower costs of living, then the cost of labour drops, that is to say more people are willing to do the same work for lower wages than before. That means that firms can purchase that labour more cheaply.
Nobody is entitled to anything here, the price discrimination is simply the result of the market correctly allocating resources, and that's a good thing, because it really does not make much sense to hand surplus profits to starbucks or to tech workers.
One very simple reason why the latter is really bad, if a lot of tech workers suddenly sit in regions with lower costs of living their high salaries will rise the costs of living, creating a huge problem for all the people in the regional economy who don't work at Facebook.
if they deliver me same coffee through email then yes, I'd expect both coffee to cost same since i don't really care where they make it, i just want coffee same as employer should care only about productivity of WFH employees
