Why is no one taking this field by storm if it's actually a more practical solution?

Because there isn't as much money in it as in ginormous megaprojects? E.g. the "train to nowhere"[1] in California had the support of a Teamster leader because:

   The legislators in Sacramento got it right
   when they voted to fund this project since
   it will help hundreds of people find good
   union jobs

and his quote continues

   and the high speed rail line will provide
   a viable alternative to car and plane travel
   in the state.

I don't think that HSR from Madera California to Bakersfield California will be a "viable alternative" to anything.

Follow the money.[2]:

   a catchphrase ... which suggests a money trail
   or corruption scheme within high (often
   political) office.

Same with water. Too many dollars at stake, and too many special interests, for simple commonsense solutions to be "practical".

[1] http://www.laweekly.com/news/california-bullet-train-to-nowh... [2] https://en.wikipedia.org/wiki/Follow_the_money