Not if you look at the per-cert pricing, but if you factor in the cost of "dealing with incompetent sales" and "convincing accounting to keep the contract going", they absolutely are.
When I was working with Digicert a decade ago, it was expensive, but they also had knowledgable support and with a wildcard cert, they would issue all sorts of 'custom duplicates' by request that were super handy. No incompetent sales, but certainly you do need to make sure accounting will pay.
We pulled all of our business after they failed to renew a cert with 30d(!!!) notice and got themselves stuck in a loop of useless org re-validations.
They were completely unresponsive and wasted dozens of hours of our time trying to rectify the situation before we pulled the plug and switched everything to ACME. I still can’t believe we wasted so much time and money with them.
It's not only the sellers of the other party. You have to work with the buyers of your company too. Stuff that costs no money and needs no contracts move faster than stuff that must be negotiated, agreed upon, paid for.
The other CAs aren't prohibitively priced for anyone who has a business need for lots of certificates, in case Let's Encrypt disappears or goes rogue.