You aren’t subsidizing Uber/Lyft just by letting them use the roads like everyone else.
Can you quantify (ballpark) the amount of money we're losing out on currently as far as roads and associated infrastructure goes? I imagine it's near zero as payroll taxes don't fund those, and the contractors are still paying taxes.
It's kind of silly to make the distinction between which taxes fund which programs. It's completely arbitrary. Dollar bills are dollar bills
At the end of the day if bills get bigger I can always pull money from gig B because I own the income stream. Just because I can currently accurately apply these arbitrary labels doesn't mean those labels aren't arbitrary, and it doesn't dictate what I will do with that money in the future.
It would be a bad idea for the owner of the income streams to actually make spending decisions based on the size of each income stream. You should always choose the expenditure with the highest expected value.