and they rely solely on volume and repeat purchasing

Yes, and it's killing small businesses! I guess, if people are willing to pay a bit more to book through a human being - they will get more!

OTA’s have successfully monopolized internet traffic for this service and sell it back to businesses at a premium! You get nailed by their commissions but if you’re not listed with then you lose out on business

This is the reality. It's a dog-eat-dog world.