The question is whether that competitive advantage will outweigh the incumbency advantage of the massive current players in various industries.
Sure, the small fry ABC IT Consultings of the world might get their lunch eaten by sharp new outfits that don't have to foot the cost of a floor full of downtown offices, but a behemoth like Dell, particularly one that has already been paying those costs as long as they've existed and has them built right into their structures, isn't going to be nearly so easy to dislodge.
This is one of the huge downsides of allowing so much consolidation across the board for decades. The incumbent players become much more resistant to disruption through changes like this—it will take a huge percentage of us, the tech workers, firmly saying "no, we will not accept on-site-only jobs anymore," to make a real difference.
this is not limited to tech
Tech just happens to be a place where almost every job can, with appropriate management and support, be done fully remotely with no meaningful loss of productivity.
This only applies to companies with large real estate portfolios that play real estate as a side hustle. If you mostly rent, just don't renew your lease. If you're an office space REIT, it's gonna be brutal.
While we seem to be on a backswing a bit from it, eventually supporting WFH will be a matter of competitive survival. Office mandates will be the next hallmark of legacy firms who have become inefficient and wasteful in their spending.