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.
Believe me, mmc code was changed and GPU mining was blocked. You can see this changes in mmc sources.