Haven't read all of the comments yet so forgive me if this has been mentioned - but bear in mind that PE is only about £5 as opposed to what, nearly £20 for PC? (Not sure of dollars.) Sure maybe PE has sold more copies, but maybe the fact it's a lot cheaper means a lot more people will buy it, not play it a great deal, then forget about it - whereas spending £20 on a game is more of a commitment. A year or two ago I bought Minecraft PE as I'd never played Minecraft before but was interested. After getting into it and reading stuff online about the wonders of the PC version, I made it my priority to get a laptop so I could play Minecraft PC. Within a year of playing PE I got a laptop and PC Minecraft, and now, over a year after buying MCPC I still love it and play pretty much daily. Whereas recently, I've updated MCPE out of curiosity and had a play, I still don't find it close to as good as MCPC. Even if all the features caught up to the PC version, the controls of a PC/laptop make MCPC the pleasure that it is to play. So maybe even though there's more sales of PE, there's still more players of PC if that makes sense? I might be wrong but just a possibility I thought was worth suggesting.
That aside, I do agree that it's pretty bad they're renaming the original Minecraft and making the console versions just "Minecraft". But I think/hope for a large amount of players, Minecraft PC will always remain "Minecraft".