^ This is a great question that pops up a lot of SSF. I'd like to hear somebody with expertise answer. IMHO, I don't think it's blatant shortsightedness on anybody's part and suspect there are material issues, for example:
1) Traffic Impact Study - chicken/egg with light rail
2) Unit Cost - Will tenants pay the premium for a high rise? Does Austin have a market segment who would pay to live in a high-rise outside of downtown?
3) Market Saturation - Similar to above, perhaps the rental market is not large enough to support a multiple tall structures
4) Developer Familiarity - Different contractors, skills used for high rise project
5) Developer Access to Capital - tall buildings cost more, right? I could be wrong.
6) Zoning - Any height issues here? Was there a master vision for Riverside?
7) Neighborhood Pushback -
Dumb, Dumb, Dumb!