I can't speak for the places that you contacted, but I know where I work there was a large amount of work for a staff that hadn't ramped up to meet the demand. There were people who coordinated closings that were working 80+ hours a week for almost a year in order to barely keep up with demand.

"There must be some pretty large moats in this industry because most shops are clearly not competing on competence or customer service."

There is. It is a capital intensive business that has licensing requirements for every state that you do business in. There are mortgage companies that will loan you the money and then turn around and sell that loan to an investor who would then service the loan. There are also mortgage companies that will loan you the money and also service the loan for its entire lifetime. In the case of the former, you can make your money back relatively quickly as you should be trying to sell the loan to an investor around the time of closing but there is risk in doing so. If you haven't done your due diligence about the borrower and something negative about the borrower comes to light (such as borrower lying about income) then the company that is buying the loan can pull out and now you are on the hook for a large loan that you issued to somebody who may not be qualified. With the latter, your income is going to be slow at first since you would only be making money from monthly payments.

I think this is because many mortgage processes are still old timey and rely on manual interactions by telephone and e-mail. So if they are busy and overwhelmed, they can’t respond. Even when people try to dump new business on them.

I refinanced in fall of 2020 and contacted a few companies off bankrate. Some send spam automailers, but better.com had a quick first contact and everything else was automated and quick. The estimates were autogenerated so no waiting on a loan officer to create spreadsheets and fill informs. And all the underwriting was tracked through a web site so no manual emailing or scanning or anything.

It was a pretty efficient process and it was nice to not have to wait on humans. I did have to cal once or twice and they were very responsive.

Pro tip: Ask your realtor who they recommend. Every serious realtor has a small group (1-3 max) mortgage brokers who they they have vetted. They periodically refresh their list if someone isn't getting it done for their clients as expected. There are lots of mortgage brokers out there, the realtors know who is good and who isn't because they work with them every day.

Also FWIW: Even here in small town America, lenders are dealing with tens of millions in volume every day. You will build a relationship with them over time, not on. any single deal.