Don't be pedantic. When people talk about NoSQL they're talking about more then a meme. They mean the various implementations: Cassandra, HBase, BigTable, Tokyo Cabinet. All these were designed from day 1 to scale to TB+ datasizes, and all do it pretty well.

Scale: handle tons of data, respond quickly, be able to grow across dozens, if not 100s of hosts.

Actually, the real problem is that MySQL sucks. Sure, you can patch over some of its suck with Memcache, but at somepoint your still stuck waiting 30 seconds for a query to return, no matter how optimized you make it. Yes, it's trivial to get Oracle and MSSQL to scale to billions of rows, but those cost money no one is willing to spend. NoSQL is wonderful in that it scales easily and is free.

Sure, you have to denormalize your data, but you probably already were to try to squeeze the last bit of performance out of MySQL.

You want people to use RDBMS? Make a free one that doesn't suck donkey balls and they will.