It's not a sustainable profession though; taxi drivers traditionally were career jobs for many in past decades. My friend's wife's dad is a taxi driver (in south america) and owns his own house, has raised a family of three and lives comfortably and is near retirement.
Now we're on the cusp of replacing taxi drivers with robots. While there are some that lean on Uber as a full time job, it's never been sold as a full time job, and second, it's been in the news for years now that the plan is to replace all human drivers with robots. It's unreasonable to expect to make a lifetime living from a company like uber, when the company is broadly advertising that they expect to replace their contractor workforce with robots.
TIme and time again they try and compare themselves to industries like healthcare, education and airport workers - industries that can't be fully automated. But their industry is being actively automated. There's zero reason to give benefits to these contractors in the long term, which seems to me why they're disinterested in providing benefits and pay increases to a market that has a seemingly limitless number of college students willing to work for any price.