This is absolutely what is going on in many US companies, no question. That's a separate can of worms for the political and legislative arenas, and not one that individual salaried employees can safely change on their own within their company. Discussions about this also tend to drag in meta-discussions about compensation, project management, management accounting, work environments, etc., adding more worms to the can, and even more cans of worms to the original can. It's messy.
What you outlined is definitely what should happen. The jobs situation is bad enough for many fields outside of our own, and even many areas within our own field, that flagrant flouting of salaried exempt labor laws is allowed by regulators, and encouraged by shareholders. Longer-term, this only hurts the companies, because they're receiving imperfect signaling of actual required effort, distorting all future projections; competitive advantage accrues to those companies that accurately and precisely calibrate their projections to known required effort. Change will come slowly and haphazardly, if only from the ongoing population growth slowdown, hopefully.
If taking a day off during a working week causes them additional effort, it is only because they are grossly abusing the definition of salaried employee the entire remainder of the year.
If they want to handle employees as though they were hourly, they could just stop lying about their people being salaried exempt employees.
If you are salaried, and your manager is fine with you taking Fridays off, payroll does not need to know. If a deadline approaches, and you need to work Saturday and Sunday, too, payroll does not need to know. Salaried workers are supposed to be paid for getting their work done, and not just for punching the clock.
It seems as though many employers are abusing the legal definitions in order to bend labor laws.