When I last went to an electronic store like Best Buy a few years ago, I think there were not a lot of computer parts like internal hard drives, RAM, video cards, and sound cards for sale.
But, most electronics stores did sell accessories like keyboards, speakers, mouse, and external hard drives.
I mostly buy PC parts online as well, or I buy them from a local computer repair store which has a website where I can check the price and to see if it is in-stock online before buying the part in person if the store is not too far from my home.
Otherwise, If the parts are not available at local PC stores for a good price, I use Amazon, and eBay to buy most of my PC parts.
It is somewhat harder because keeping current requires more cost (mainly CPUs and GPUs here) because good ones tend to be higher priced while more budget ones are outdated quickly. Meaning that budget ones might very well sit on a shelf for 9+ months, losing most of their retail value in the process so that they're even harder to sell. (Who wants a mediocre graphics card that's also a year out of date? Especially when budget cards already are usually worse off.) And the high end ones aren't something most people would be wanting to buy. I mean some of them can easily cost up to $600-800 alone. So stocking them is a riskier proposition because they're likely to sit, taking up space, and if they don't sell then they likely won't so they'll have to be heavily discounted or tossed out/sent back and fresh ones brought in.
Plus the internet being so prevalent allows people to order the exact parts they want and have them shipped directly to them.
