Code was changed. This is a fact.
Exactly after that all major pools (mmcpool.com and 1gh.com) delisted mmc.
And people lost interest to mmc, because ask yourself - how many people has Xeon servers?
Also, yam-miner main problem is a proprietary closed-source code with hardcoded (dead now) pools.
I know there was a code change when MemoryCoin Beta and ProtoShares transitioned to MemoryCoin 2.0 (MMC2). After Delinquency took over MMC2, I remember a hard fork sometime in the second half of 2014, but I did not realize that was a major algorithm change. I also remember dwarfpool.com and 1gh.com delisting MMC2 around that same time-frame.
It was never my understanding that GPU mining was dead due to code changes, but I could be wrong. I just remember the GPU mining discussion dying when yvg1900 released YAM with MMC2 support.