I am already paying enough taxes to not be happy with paying for nothing with my own time on top of that. Every year the tax rate increases but the number of trams and subway trains is still the same.
They are extending into suburbs, not anywhere it's relevant to most Prague citizens (extended city to city centre). They even decreased the number of trams going from our stop (a pretty major one, because it's the nearest city stop for the airport) into the city centre, and the number of subways is constant.
The D line is a meme at this point, it is supposed to be finished for 20 years now.