Yes, something similar happened to me too. I've known forever that my wisdom teeth are impacted, (grown in totally sideways, at a 90 degree angle under my gums.) I was always told I would probably need to have them taken out. I'd be lucky if I made it to my 30's and they didn't cause a problem. (My mom didn't have hers taken out till then.)
Ten years ago, my teeth shifted and started crowding a lot. I used to have braces and perfectly straightened teeth. I read that people who have had braces might later have a problem with teeth shifting,
so it might actually be an orthodontic problem instead. 
But I also thought it could be my wisdom teeth finally moving, so I saw an oral surgeon about it.
He was surprised that my wisdom teeth had lasted that long. While he didn't see any immediate, emergency situation, especially as I'm in no pain & they don't bother me
at all other than the thought of the crowding, the x-rays indicated there
may be a cyst in front of one tooth and
possible abscessing in the other.

He said I
may have a potential problem in my 50's. He wanted to take the bottom ones out NOW as a preventative action.
The top ones, which was my bigger concern in regards to my teeth crowding, he wasn't even touching.

So, the extractions wouldn't fix the crowding at all.
I felt his
preventative diagnosis was all well & good - if I had the money. While insurance would pay quite a bit, a hefty sum would come out of my pocket.
I was also quite a bit cynical, especially as it was during the downturn in the economy. He was highly, highly recommended to me by my regular dentist. But, his waiting room was
empty and they were practically able to fit me in for an appointment at any time, for the consultation and the extractions.
Of course, the extractions would be beneficial to me. But I wondered if this expensive,
preventative operation - when there's no real immediate problem, may be more about helping to pay the dentist's rent.
I decided NOT to get my wisdom teeth out. Instead, I went to a cosmetic/aesthetic orthodontist. He put on laminates over my front crowded teeth, so they are perfectly in alignment again.

Plus, he said the extra thickness would help stop the shifting. AND he gave me an Invisalign retainer, just in case they do start shifting.
I never regretted my decision. It's been 10 years. My teeth stopped crowding. And I never did have a problem with my wisdom teeth, so far.
I think your dentist wanted to use your insurance to line his pocket. SURE, the procedure is beneficial. But necessary and had to be done at that time? Probably not.
As for him charging you the full amount for a crown, I don't think he can. All you have to do is take a photo/x-rays(?) of your teeth for verification that no new crown was ever put in. He may charge you for the time for the lousy imprints, but not a crown.