It's not sharing if one person is still paying another person for a good or service. It's just cutting out a middleman (or two or three). This has the potential to be a great thing, but it's still not sharing.
My girlfriend showed me an internet cleaner service I wasn't interested, as I view that as a middleman taking their cut, and cleaners are already pretty poorly paid. I would rather go on word of mouth recommendation / or an add in the local shop noticeboard, as I did before this sort of service sprung up.
I view Uber or Airbnb as a monopolized version of the middleman.