> Taxis are 4x worse
It really depends. One city I travel to fairly regularly, I tend to take Lyft because it's cheaper but I'm really indifferent to taking a cab vs. taking a Lyft for any other reason. In fact, I sometimes take a cab from the airport if there's no line and cabs just sitting there because it saves a few minutes.
Yes, taxis are generally bad in quite a few cities but it's not universal.
Taxis can't undercut them. Even if Uber were 2x as expensive, that would be ok because Taxis are 4x worse.