A second barrier, is the difficulty in finding patient-therapist fit; IMO it's worse than trying to find a kidney donor, unless your problems are very mundane (litmus: does a Hallmark card cover this?)
So, access to real therapy is already hard to secure. Talk bots offer a convenient and affordable alternative. Most people will thus be fobbed off on bots that are also snitches, sycophants, and occasionally incite violence and self-harm, but that's what we have personal responsibility for, hmm? It's terribly convenient for mis-ascribing blame.
Finally, there is every reason to expect that for many people there is no "transference" or deep therapeutic emotional connection with LLM therapy, and, if there is one, it's an attack surface now.
In other words, the new "therapy" will be risky, ineffective, manipulative and sycophantic, so it will, in the best case scenario, do nothing, and in the worst, quite a bit of harm.
But it will be very popular. Like astrology.