The barriers to entry with ride sharing are absurdly lower than anything else on that list. The network effect is pretty weak, because it doesn't cost consumers/drive more time or energy to keep multiple apps on their phone.

Other than pharma, you just mentioned 3 industries that have very low margins. They aren't making a ton of money on their monopolies.

Indeed I think he proved my point.

I am not sure who would like taxi industry to pharma?