They "ruined" the taxi industry because it was anti-consumer and absolutely horrible. That's why it was so easy for them to "ruin" it (read: make it so much better).
Seriously, you think it's "ruining" an industry to have a convenient smartphone app instead of having to call someone on a phone and hope a driver shows up within 2 hours? And then have a driver that doesn't use a taximeter, drives around in circles, and just makes up a price on the spot? Maybe you never tried using cabs in the suburbs before the invention of Uber/Lyft.
Seriously, you think it's "ruining" an industry to have a convenient smartphone app instead of having to call someone on a phone and hope a driver shows up within 2 hours? And then have a driver that doesn't use a taximeter, drives around in circles, and just makes up a price on the spot? Maybe you never tried using cabs in the suburbs before the invention of Uber/Lyft.