May I also bring up two points?
I do think Sonic Lost Worlds was intended to be a main series game. Why? Because it follows the same plot line as the main series of the games, even though it kinda steals some of the plot from Colors.
Sonic Boom actually was hyped up a LOT by Sega. I follow them on Twitter, I should know. I've seen it the past few years. My friend, a HUGE Sonic fan, was hyped for it. Sega even made a TV show for it and anything. So how is this a side game? It seems like Sega wanted this to be a reboot if anything.
BTW, that same friend has lost hope for the Sonic franchise. You know why? Because he feels that Sega has lost their touch. And this was a guy who debated with me when I was younger on which was better: Mario or Sonic? Good friend, but he understands that Sonic just isn't what it used to be.
Better to end it now before it soils itself again. Maybe make a return, like BIONICLE did.