Agreed, but the problem with Texas is the size - you have to know where to spend and focus in order to get the maximum benefit and turnout.
Democrats and Republicans have spent YEARS researching and placing targeted ads/offices in specific counties in swing states like Arizona, Nevada, Pennsylvania, Michigan, and Georgia.
They would need to do the same with Texas which has more large cities than any potential swing state. So you are looking at targeting demographic groups in 5 of the 12 most populous cities in America - Houston, Dallas, San Antonio, Austin, and Fort Worth.
That's not even including El Paso which is on the other side of the state - and El Paso is bigger than Detroit, Las Vegas, and Milwaukee (the MSAs are bigger but the cities themselves are smaller).
It can be done but requires a large investment in time, money, personnel, and infrastructure. It's the kind of thing that needs to be built up over several years.
They at least have an idea where to spend in Florida due to its history as a swing state.