Are superbills that hard to generate?

To be clear, I am a client not a provider, but I wanted to ask this question to see if there is any context I'm not considering from the provider/billing side. I'm experiencing a situation with my new therapy office that I wanted to share details of and see if this is normal or if something is awry in this billing department.

For context, I've been to multiple different therapists over the past ~10 years. Usually I'm able to submit directly to insurance for in network coverage, but I've had a few experiences where I need to do the whole rigamarole of getting the superbill and submitting for reimbursement. At my current therapy practice, I was initially told I was in-network. Then, a coordinator from the finance department called me and told me I'm actually not in network with them and have to pay the full balance for my past 6 sessions, which was $1200, immediately. I was not expecting to have to pay that cost all at once since I was anticipating full insurance coverage as I'd been having, and I'm dealing with other family financial issues (my dog has cancer and her treatments aren't covered by her insurance either so we're paying thousands out of pocket) so it just sucked to have another large unexpected cost come up with no apology on their end, when this was an error on their internal billing processing side.

Anyway, this is the second therapy practice I've been with in my life where asking for the superbill document to submit to insurance for reimbursement is like pulling teeth. It just seems like a really unfair double standard that I have to pay this huge amount up front and then have to call, email, follow up multiple times just to get the superbill PDF from them. I understand these billing departments are likely understaffed and this is probably a not-fun part of their job, but unfortunately with how long insurance reimbursement takes I literally cannot afford to be out that much $ each month while I wait for insurance to repay, or I'll have to stop seeing my therapist. I had just fully gotten comfortable with this new therapist and really don't want to start over with someone else, but this billing struggle is making it really hard.

I'm hoping someone can offer me context from the back end of why it might be hard for providers/billing coordinators to create and send these superbills? I'm not asking for a weekly bill to be created on my behalf, but the coordinator at my current practice told me he typically only sends superbills to clients every 6 weeks. Like I said, being out $1200 a month while being in a constant cycle of waiting for reimbursement is unfortunately not gonna work for me. I wish I had the disposable income where I could be more relaxed with that timeline but I just can't.

Any advice on how to approach this billing situation thoughtfully while also communicating the urgency of the situation would be much appreciated. Thank you!