The thing is that the cost of such projects is an investments and a legacy for future generations to enjoy. Imagine if we had to build the BART or the highway system in this they and age. How much would it cost? How many buildings in highly concentrated areas will need to be taken down to make way? Do you even believe that BART was on budget or on time?
Would it be any cheaper to build a high speed rail system in 10 years? In 20 years? Should we throw the towel and decide that future generations will only have the option to fly to LA or should they have to build it themselves at an even bigger price tag?
I know the HSR project is going to be over budget and the ROI won't be there for my generation. But in the same way that I can commute to SF on Bart, I want future generations to have the option to travel to LA in HSR.