I haven't played pool in a bar for decades. Just newly re-interested in pool.
Great news. Since 1990, most of the bar boxes have evolved. The ultimate is the Diamond 7'
I was wondering, are bar tables essentially the same as they were 30+ years ago, except perhaps the number of quarters for a game?
If you consider the Diamond 7' table, no they aren't essentially the same. Not even close. See the summary at the end.
The arcade quarter drop still exists, but a few companies have different styles to include tokens, bills, pay per time, etc. Diamond is pretty flexible as I've seen at least four different methods on Diamond tables (quarters, pay per time, tokens, and US Dollar coin). I'm sure there is no issue fitting the bill or credit card, or any other new way to pay.
Are there any debit card operated, or Samsung Pay, or other NFC mobile payment tables?
See previous
Any play queue management technology?
Well, some tables still have the quarter holders, but certainly that's not a normal thing anymore. I don't know that any table manufacturer has looked at queue management. A chalk board is about the best thing available. Got any ideas?
Do they still recognize the cue ball by size, or magnetically? I was thinking a 21st century table could have RFID tags in all the balls, detect them as they drop, and return balls or not based on what game one has paid for.
This is where the meat of your question really points to Diamond Billiards and the evolution of the 7' table. Diamond leads the field on this important question. The whole table plays like a regular table. The cueball return is based on an optic system that differentiates the cueball from the other balls, so you can use a real, normal cueball instead of the oversized cueballs of the past.
Valley/Dynamo's cueball system uses a special cueball today with a jacket of ferrous material post-cast on a object. The result is roughly the same weight and size cueball that can be pulled to a return track with a magnet system (a more evolved system than the magnetic return systems of the 1990's. So even Valley has evolved. But the Diamond system is just overall way better.
To your overall questions, yes Bar Box tables have evolved, with Diamond easily lapping the field. If you haven't seen one, you will be pleasantly surprised. They use the same cushion mounting style as a regular table (not the screw-in-from-the-side that most bar tables have), the pockets are nearly identical to standard pockets, there are no metal corners, and the cueball return system allows a regular cueball to be used.
If you have any questions, RKC is your man.
Freddie