At least unions can still exist inside the standard model of employment which everything else is built around. In a "benevolent" tech company that actually treats its people well, I have trouble seeing unions as the ideal vehicle for balancing fairness with innovation. Of course there is inherent exploitation in any employment relationship within the standard model. I would love to see an example of it working in tech though, because I can imagine a union that is equally as interested in the success of the business and prioritizes sustainable growth on top of enforcing equitable treatment as a backstop.
There has to be some combination of legal structures that can somehow represent all interests fairly without adding friction. That is unions, or unions plus other things.
For example, employee ownership trusts could in theory be very aggressive and help smooth out the continuum between periodic bargaining and striking as the main/only leverage. Similar to a share purchase plan or RSU with a pool that has a majority of voting power, or at least equal to founders and investors with all the usual tie-breakers and dilution protections.
If I remember correctly some countries (Germany?) also have legislation requiring a certain amount of employee representation on corporate boards, but I don't know if that actually makes a big difference.