I will be answering this to the best of my knowledge as a therapist that accepts all major insurances.
The short answer is that insurance companies can be very difficult to communicate and work with through all parts of the reimbursement process. Behavioral health is its own branch of healthcare service, and many insurance companies contract it out. So you need a contract with the original company, and then whoever they contract out to. It’s a convoluted process to get paneled and reimbursed.
Another factor is reimbursement rates. This work is the clinician’s first line of income (many of us have side hustles), and an insurance company’s reimbursement rates might not match the clinician’s rates for self-pay.
Lastly, being a self-pay therapist allows for the most freedom for practicing clinical judgment. When insurance companies provide reimbursement, they are allowed to do records requests and dictate if they feel a client should continue treatment, decrease treatment frequency, or in some other way altar the treatment plan. A therapist can, of course, appeal an insurance company’s decision, but this is unpaid time.
So like with most things in life, there are pros and there are cons. I decided to accept all major insurances (including Medicaid) as access to care is an important guiding principle for my practice. But if you’re having a hard time finding a therapist that accepts your insurance, you’re not alone. I would encourage you to keep reaching out.