Lots of posts about the "good old days" and wood yards now no longer part of the landscape. I understand the sense of loss but we as customers are largely responsible for the change.
When new suppliers (DIY and Trade) emerged they no doubt offered lower prices, bigger stocks, faster delivery, better supply and distribution network. Small suppliers could not compete with their buying power and investment. We were no doubt very happy with the low prices and other benefits.
There may be other factors in play (my ill informed guesses!) - cheaper transport, fast growing vs old woodland, economics of kiln drying vs traditional seasoning, automated processing etc.
This is no different to the demise of independent butchers, bakers, greengrocers, etc mostly replaced by a few massive supermarket chains. The pandemic rapidly increased online purchasing from sellers without the overheads associated with traditional businesses - the high street is changing or dying.
I am as responsible as any for surfing to find deals - woodworking supplies, food, clothes etc. If we value the old, traditional, knowledgeable service, etc we need to pay for it.