
In the past when I have had tarty willing bitches who all mated naturally needing no restraint and only their collars held for reassurance during the tie (not even that on further matings) I would have agreed with you.
My champion bitch has very high Libido and mounts and allows her female companions to mount her when she is in season. Yet when it came to it, she was very difficult to mate.
She would move at the critical moment (she would thrust her pelvis like the male instead of accomodate the male), or refuse to be mounted but would mount the dog instead and get very over excited.
She would have made an excellent stud dog as you literally had to peel her off the poor male

Now this is not a bitch that is unwilling or not ready, but one that is very sexually dominant. I am sure with a very dominant male she would have been fine, but sadly the mates I had chosen for her were either young or inexperienced.
After a second attempt at getting her mated we got one mating when she was distracted and held and had a litter.
Next time same male she woudl have none of it.
So I had her live with the boy from the time she next came in season. She liked the idea much better but still had the problem of her reversing gender roles

So when she was obviously ready I had to hold her rear still with all my strength to stop her moving at the critical moment (I had spent two days on my knees and the poor dog had made himself quite sore from the failed attempts). We got a top class litter.
She absolutely hates the tie though and you need to hold on like grim death to prevent her injuring herself or the dog. She was still happy to be mated again, though still held her to make things easier for the male so he didn't wear himself out. she would still pester him unmercifully straight after.