all of the attempts to rationalize this as fair or unfair are not useful - i'm guessing most SWEs will accept big salary cuts to work from wherever they want in the country. hell, a large portion of the SWE crowd is willing to distribute their labor /for free/ in the form of FLOSS, so i have no doubt that they will not hold the line in any sense if big tech starts implementing this in earnest. add to that fears of another tech recession (e.g. VC money drying up) and mean big tech SWE salary may drop a fair chunk.
anyway, on the plus side, there may be a large cadre of talent available on the cheap - seniors willing to work remotely on a more mission-oriented project from their bungalow in Ohio. so it's probably a great time to start a software company, or might be shortly.