so salaries. How the fuck are they determined
Not sure how yours is determined because I don't know what you do, but in software there are contractors that charge exorbitant prices to do like the most basic programming task. So if a company pays a developer a salary, they don't have to do very much to make it extremely worth the while of the business. Like if someone makes 80-100k per year and develops like an api layer using cloud services, maybe a few months work, it's already more than paid for itself. Anything else they work on that year, or doing tech support work, is basically free. I have a friend who writes yaml configs for azure services and makes incredible amounts of money, but works very little. But like you say, you have to always be by the computer. So even though the pay is high the work is still exploitative.
The question betrays an unspoken fact about capitalism: technological development is only invested in when it lowers the cost of wages (eliminates workers.) Capitalists don't invest in tech advancement for the sake of advancement. If a technology already existed that could be invested in to replace workers, it would already be known about in the trades and chances are the capitalist would already have invested to stay competitive. If not, the cost of r&d to develop a solution, especially when capitalists make exorbitant sums off of the surplus labor of workers, is going to cost more than what it would to pay the workers a little more.
Large businesses with existing investments in capital, this is probably more true in a modern setting, since new technical advancements capable of replacing a vast swath of workers would require replacing that capital with new, bespoke, experimental machinery. This just isn't that common for existing large production operations. This is where smaller "interruptor" start ups enter the market, which brings me back to my first point. There's always the possibility of it happening but if it does it was going to happen anyway. Capitalists aren't paying workers out of the goodness of their heart, and striking will make them decide to invest in new tech. It's market competition that forces investment in new tech. I would say that most of the time those are just empty threats.