The "gig work" jobs crowd out other, better-paying and/or better-benefited jobs because the companies brokering them (Uber, Lyft, etc) are able to operate without turning a profit.

It doesn't help that these jobs often have an attractive shine to them up front—fast, easy money! all you have to do is drive around!—but hide lots of costs—like massively increased wear and tear on your car—that there's no advertisement about, and no help in covering. If you have to keep driving to keep food on the table, it's also that much harder to take the time required to find a better job (though admittedly, that's not really qualitatively different from most low-end hourly-paid jobs, though it may be quantitatively, if your expenses end up wiping out enough of the income that you're effectively getting less than minimum wage).