Start with what is at least partially true. The US could always produce more oil, and Texas can also produce more oil. Maybe even enough to make up for the 6-8MM barrels a days which the US imports.
But:
1. You can’t just increase production in a day, a week, a month or a year. To increase oil production by the amounts involved would require immense amounts of capital, not just for drilling, but also for services and infrastructure. Those who supply the capital would want to see that this is a long term investment. Even if wells in the Permian have pretty quick payouts, facilities like pipelines, storage and refineries, don’t.
Since the US is currently producing historical record volumes of oil, there is no excess capacity for additional large volumes of oil, let alone the millions of barrels you would need.
2. You won’t necessarily produce the type of oil which US refineries are configured to run. Many refineries need heavier grades of crude which tends to be imported (mostly from Canada lately) or synthetic crude, pretty much all of which currently comes form Canada.
3. I could go on but I think that’s enough.
The bottom line is that the US supplying all of its own oil requirements is, so to speak, a ‘pipe’ dream.