1. There is symmetry of information in the economy (users will know when their data is being monetized)
2. There are many providers of a service with different offerings
3. The services are commoditized (there is nothing keeping me from interchanging one for the other)
None of those assumptions are true for all services and only a few services may meet all 3. #1 is the least true IMO and if you want it, it’s something you’ll have to pass legislation and regulate for. There’s not much you can do for #2 except make it easier for people to make services, sometimes economies of scale and network effects mean that it will only make economic sense for there to be 1 player in a market, in that case there should be heavy oversight on that player, such is the case with public utilities. #3 would require standardization, this can be done by industry, but they have every incentive at this point to silo their users. Public and Gov’t pressure could make this happen similar to the formation of the MPAA as a hedge the movie industry made against gov’t regulation.
All of these have value, but are needed for various aspects of business (sending purchases, receipts, contacting you on case of issues with your account, etc).
For that matter the compiled list of actions you take on a site have value. The only way not to provide a service with valuable personal information is not to use it.
(I guess this technically assumes that voting with your actual vote also works, at least for the purposes of removing abusive know-your-customer laws, but lack of gratuitously harmful regulation seems in line with the libertarian-esque philosophy behind "vote with your wallet", so... eh.)