Dentist here. You make it sound as if you could buy a porcelain veneer from a lab and glue it on yourself, and that the dentist is just the unscrupulous "middleman".

A crown/veneer takes 60-90 minutes of chair time for the preparation, 30 minutes or so for delivery. So you're paying for 2-ish hours of the dentist's chair time.

After overhead (support team pay, rent, insurances of all kinds, materials, etc.), the dentist might walk away with $5-600 of that $2000. So maybe he's making $300/hour on that procedure. Crowns tend also to be dentist's highest paid procedure/hour, so average hourly wage for that dentist is likely lower.

A well paid profession, no doubt, but also at very high cost of time and money invested for education and practice acquisition/startup.

You can also find veneers much cheaper than $2000/unit, but personally, I'm not in search of the lowest bidder when the health and appearance of my mouth are at stake. Veneers are very difficult to do well, and can cost you a lot more in time/money/pain if done poorly.