Why no cities on I-45 like there are on I-35?

[ADCS]

Had a long screed written out about this that got lost, but here's the gist of it:

- Geology of the Edwards Plateau makes for good water sources
- Geography of the Edwards Plateau required many river fords/toll bridges, where small cities would naturally grow
- East Texas was a malarial swamp that made it difficult to establish large towns/cities prior to swamp clearance and air conditioning
- The railroad between Houston and Dallas went via Hempstead and Mexia, rather than Huntsville (why Texas A&M is where it is)
- Galveston and Dallas were actively trying to suffocate Houston in the cradle by building a railroad on what's now the route of SH 6 and SH 36
- Original improved road between Houston and Dallas went via Hempstead/Bryan/Mexia, but the highway department wanted to shorten the route by 30 miles by building a cutoff between SH 19 in Huntsville and SH 14 in Richland
- Once the US Numbered Routes system had been implemented, that new cutoff became part of US 75
- When implementing the Interstate Highway System, it was possible that they would have routed I-45 via Bryan-College Station, but US 75 had atrocious fatality rates, and the state wanted to improve that route for safety purposes.