Going over the whole thread it seems that the questions is:

after buying a bike at a LBS, where they saw the buyer and knew the buyers weight and hopefully riding style and subsequently there are ongoing wheel issues what is reasonable to expect from the shop?

there are some things I haven't figured out from the thread like OP's weight, exact bike, wheel specs and riding style that may have bearing.

It seems to me that the first thing a shop could/should do after several wheel issues is to completely untension all spokes and retension and true. This is labor which is expensive to the shop, but could resolve the issues. The shop could offer to swap out the spokes for high quality stainless also, as spoke quality is more of an issue than rim or hub and once you break one spoke, the extra stress until that spoke is fixed will almost guarantee future issues unless you swap all the spokes.

Offering a deal on a new wheel or wheelset is another option, but in a way this feels like a workaround if the shop wasn't upfront with saying just to note because of your size, riding style you may have issues and might need to swap wheels out in the future.

For what it is worth I am 273 (was up to 285....it is starting to work yeah) I run 32h sun cr18 rims on deore hubs on my commuter/utility. When I first got the wheels (via ebay) I had some spoke breaking issues, especially on the back I rebuilt the wheels, using a tension meter (first wheel build) and have not had a problme since. My road bike is 32h Velocity Deep v with ultegra hubs and double butted stainless spokes.....built the wheels (but had my local wheel guru do a fine tune) and again no problems. So having a hugely overbuilt wheel may not be needed, depending on your size