OD&D - 3LBBs vs 3LBBS + Supplements

A number of people all over the web have made the assertion that 

3LBB gaming is really an artifact of the OSR movement rather than something that actually happened at the time.

As I have noted elsewhere, I don't buy this assertion. People certainly used only the 3LBBs with or without Chainmail until Greyhawk first came out 14 months after OD&D was published (Blackmoor came out 20 months later). The ref that brought OD&D to college in the fall of '75 started us out with just the 3LBBs even though he had Greyhawk and I started reffing with just the 3LBBs. After I had reffed a for quite while then he brought out Greyhawk and we jointly decided what to try and keep and what to try and not keep. Perhaps I am wrong, but the vast majority of OD&D players the first few years were adults or young adults and I find it hard to believe that the majority adopted each supplement in toto as it arrived. 

The main things our group adopted were monsters, spells and treasure (which I don't to some extent view as house rules since they are non-mechanical in nature.. The new mechanical things are what we carefully considered before trying. He used more of the mechanical things than I did. My preference has always been the 3LBBs plus house ruled spells, monsters and treasure from where ever I found them or created them. I have always preferred to limit the mechanics to the 3LLBs or to tweak those mechanics and try different things. IMO the stat bonuses introduced in Greyhawk are a slippery slope and while I have used them from time to time they are not my preference. I have a hard time believing that bitd I was completely unique in that regard. Perhaps the percentage of people who preferred the 3LBB mechanics to Greyhawk mechanics were not the majority over the period running up to 78-79, but we were certainly not non-existent either.