@marynelson8 The problem is, "STOP" only works if they're legitimate. If they are legitimate, you can just block the number. But if they're not legitimate, then you've just confirmed you're a real human at a real number to a scammer and you get far more spam as a result.
As you noted, the fact that they can spoof their number means conventional blocking doesn't really work either.
However... Most cell providers offer a service to report these kinds of texts. In my case (AT&T), I can forward them to 7726. The more people who do this, the quicker those companies can identify the source of the spam and cut it off (these texts annoy their customers and cost them money; they want them gone too!).