BTW not sure why should taxi driver in Spain speak English
Because it is embarrasing to have a tourism-based economy and at the same time to be proud of not speaking any English, which is highly likely to be at least one of the common languages you are going to share with the customer.
Disclaimer: I am a native spaniard. If you are going to visit Sevilla for Semana Santa, you better have some Spanish under your belt because it's highly unlikely anyone around you speaks anything else.
>not sure why should taxi driver in Spain speak English
for many reasons I would find obvious (economic etc) but besides that: given the choice between someone with and without multiple languages the better service is multiple, so sure, does not have to but overall it helps.
Do a lot of Uber drivers in your city speak Spanish or Chinese?
It would be useful to me that wherever I travel people talk some common language with me, but I don't feel like they have to.
It seems to me that if you choose to visit a foreign country you should expect some inconveniences and adapt to the local population.
But as a citizen, I expect my countrymen to do better than the bare minimum, and learning English is part of that. I write this as a non-English speaker myself.
Maybe they should get PHd in Nuclear Physics and make some real money.
And how many existed before Uber? That's their value: they give a nice push to a complacent industry used to have a nice little monopoly. After that, it can burn to the ground for all I care.