It is certainly a luxury item, but I have seen the results of heated driveways. A close friend sells for a heating and air company that installs them. The applications each had their own gas-fired boilers, and one was a 1 million BTU unit (large installation where money was no object). I don't recall how much the approx. 40' three land driveway cost to install heat, but I seem to remember thinking it was more than $30,000. I can get info if you want.
The results are dry driveways, when the streets are wet and slippery. I had another buddy whose front door was at the base of his steep driveway. He had electric heat out of necessiity, but found it was prohibitively expensive to operate.
I guess it depends on the customer. People don't have to be rich to get a paver driveway, but certainly must have money to spare. Heating a driveway is another level (at least around here). I don't think a customer who is willing to spend the money on pavers and heat is going to be worrying about operating cost. If so, driveway heat is probably not for him/her.