TV ads don't do anything - certainly not on that scale. It's just a famously ubiquitous money pit that desperate and relatively clueless politicians constantly fill, and political consultants milk, every 2 years.
Clinton did well because Trump accelerated a shift of voters between the coalitions, and Texas was particularly vulnerable to that. I mean, it's not like Clinton's TV ads from 2016 managed to sweep Democrats into power all over the state's urban centers in 2018.
I said it was one of the reasons, not the sole reason or even the biggest reason.
Right, but what are the numbers though? This is all I can find on it:
https://www.texastribune.org/2016/10/18/clinton-texas-television-advertising-campaign-star/By mid-day Tuesday, Clinton's campaign had booked ads in Texas worth at most $100,000, according to a GOP source briefed on local television sales. That figure is small in any state, but the prohibitively expensive media markets in Texas further diminishes the campaign's bang for its buck.
Comparatively speaking, Clinton's camp will spend $2 million in Arizona, another traditionally Republican state.
It does jog my memory for 2016 too, where Texas was coming up in the news but little financial commitments had been made by Democrats at the time. That is absolutely nothing when you consider that the media markets Democrats have to play in are very expensive. Compare that to the nearly 10 million in Colorado spent up to August 2016, or 20 million in Florida, or 16 million in Ohio, and so on (
source). And those figures are only what was spent up to the summer. It doesn't include the tsunami of money in the run up to election day. Meanwhile, that link about the $100,000 TX ad buy was in September-October.
Even if Clinton spent a few million in Texas, it's still barely a drop in the bucket, especially for a state that big. If TV ads can even move the needle, for a state like TX, you'd need to invest tens of millions in at least Q3 of the election year.