The reason I probably won't ever enter another bike shop is purely economic---and if I do, the reason would be the same.
I don't have a lot of bike shop horror stories .... it doesn't take long to size up a shop, and when I used bikes shops I quickly narrowed down the field to two which were worth it ... and however many others, who cares?
I bear no grudges against any shops or LBSs in general. I don't assume most of them suck. I just know that it is Not my business to "support local business." (How many of them ever called me up looking to support me?) If a local business supplies a product or service the community wants or needs, it survives. If I decide to open a fried dog-turd stand, do all my neighbors have to come buy my fried-turd-on-a-stick? But I'm Local!
Money is too scarce for me to waste it
on charity, so when I spend on charity I do it deliberately and carefully. I do not consider supporting a bike mechanic to be a worthwhile charitable contribution. I'd rather help people who cannot help themselves, or are in situations they cannot escape or survive without outside help. The guys in the bike shop can either make the shop work, or they can get other jobs. They don't need charity. Right now everything I have goes to stopping people from being killed for their organs in China (
https://dafoh.org/) ... to me, knowing people are being arrested, held, and killed to order to provide organs for transplant is a Little more serious than the plight of the guy who cannot sell his over-priced bike parts.
So ... I will buy bike parts online ... and when (as now) all my bikes have all the parts they need ... I will Ride my bikes and not buy parts.
So ... why do I need to support an LBS?