removable batteries are becoming more rare because OEMs have decided that they aren't worth the trouble... it's not some secret OEM cabal hell-bent on forcing you to upgrade your phone. And with recent efficiency gains and the availability of portable power packs, consumers care less and less about removable batteries. Sure, there are a vocal minority still clamoring for them, but the market, as a whole, no longer bothers.
The market is cutthroat... and if an OEM can improve their position by cutting a feature that adds complexity and manufacturing costs they'll do it in a heartbeat. If it angers a fraction of their user base, so be it... you can't please everyone.