Nomad, you've summed up the situation for most if not all Farang living in and around Surin. My own visits to restaurants have been scaled down by roughly the percentage difference between the peak and trough of exchange rates quoted in your post. Rather than eat out less frequently, we've eaten at the less expensive places. There has to be a compromise though: I had some very unpleasant crispy fried chicken gristle on New Year's Eve, and would not have fed it to the dog. On the other hand, steaks at Apsara were always perfect. Yer pays yer munny and yer takes yer choice. If the fried gristle restaurant shut tomorrow, I couldn't care less, and there are probably hundreds of other places in Surin already that would provide better fare. Sadly, I have yet to visit any other restaurant here that provides the consistency of food, menu, cooking, and décor found at Apsara.
It is a game of numbers though.
A tv documentary today featured some hi-so Thai kids sampling restaurants in Chinatown. They enjoyed eating dishes that cost up to 1,500 thb each, and the waiting list at one of them for reservations is months-long. Every seat was taken (obviously) and the chef has a Michelin star to her name. They can only accommodate a tiny proportion of those who wish to eat there.
There simply aren't enough high-rollers in Surin to keep a place like that in business, and - as a result - prices (and quality) tend to be low, but new places open on a regular basis (mostly at the lower end of the quality scale) as regular as they and others close down.
Back to New Year's Eve, and ours was a party of 10. We had booked a table in advance, and the restaurant asked us to order our dishes on the day that the booking was made, stating that we'd have a long wait for the kitchen if we didn't. We sat down at 7pm, ready to eat. We were the only diners there! It remained the same until around 9pm, when others gradually arrived, and it was almost full at midnight, but not many were eating... There were more waitresses there than diners for much of the evening. This despite live music. Oddly, a second band was supposed to take over the entertainment - but they either failed to arrive or (just as likely) were cancelled by the owners as the place was still empty when the first band left.
There's little doubt that another Western style restaurant will open in the weeks or months to come, hoping to improve on Apsara's experience. A year's rental in advance should prove enough to see them out too.