Could be there's a market for this in your area -- if only for yourself. However one thing to consider is that many and maybe most of the saw blades used in construction are now, essentially, throw-aways. About as cheap to buy a new carbide-tipped blade for a Skilsaw or Unisaw as have one properly re-toothed and sharpened.
My first 10" saw blade was likely HSS, wore quickly, and probably cost $40 in today's dollars. Today a cheap 10" 60 tooth carbide-tipped saw blade is $20. Hard to make a living sharpening those, by the time you braze on a new tooth or two, shape it, and then touch up 60 teeth . . . Hardware stores around here are doing trade-ins (circular saws, hole saws, etc.) for around half new price -- but I'd assume the trade-ins are done on pretty pricey automated equipment.
There's still a need and a market for quality $100+ blades - and resharpening them. Especially for cold saws, where the blades are even pricier. But it's not what it used to be.
I suppose the silver lining is that used Foley rigs, noted above, will probably be more affordable?
