Originally Posted by
LapLap
I'm not so sure that only 'upscale' restaurants make dashi from scratch.
But it's not always to do with the perceived 'class' of the restaurant. There are many modest establishments that specialise in 'simple' dishes where the success of the food is almost dependent on the dashi making skills of the chef.
"Upscale" was a misleading and unfortunate choice of words on my part. I'd still adhere to the 99% figure. However, many of the restaurants that make their own dashi might be modest looking establishments that nevertheless take a traditional approach to making their food. This would (likely) include traditional handcrafted soba restaurants. Furthermore, many places with upscale appearances use hondashi.