Austin is not "new". It was at competition with Silicon Valley and used to be referred to as Silicon Hill. A lot of hardware manufacturing happened in Texas. At some point, between favorable business laws and Google starting large scale recruiting events it sucked a lot of the talent out of places like Texas.
So your statement is more accurately framed as, "Austin is finally recovering as a tech hub."
While businesses these days may move to SV because of the large population and other businesses, that was not the case in the beginning.
Not that long ago it was Detroit, Buffalo, Boston, Dallas, Houston, Princeton, Pittsburgh, Trenton, and more than I can count that were the bustling megalopolis' of America where you went to if you wanted engineering talent or culture for that matter.