My Scottish town of 13,000 people has 1 drive through (A McDonalds)
The Canadian municipality of two nearby towns (also around 13,000 people) has a good half dozen drive throughs, and it seems like any place with a population of over 500 has a Tim Horton's (drive through coffee and tea!).
Most are OK. Personally I find McDonald's the least enjoyable... and find most people are just after decent tasting food and convenience.