Sounds like Planetary Annihilation does have offline single-player: And take over an entire galaxy in a dynamic single-player mode with procedurally generated content.
Though I'm assuming the offline part. Mmm, tempting...
Yeah it has offline single player, it has zero story but I kinda like it. It's basically a bunch of skirmishes in a "galaxy". You start with a pretty basic tech load out and find new techs (and slots for techs) as you work your way through. If you lose one of the skirmishes, it's over.
I like it because the skirmishes are pretty quick, I can win one on medium difficulty in 12 minutes or so. Of course, I don't let the guy get a foothold.
As far as Titans being a cash-grab... as much as any other game is a cash grab. It's a standalone expansion that isn't free, much like many other games and DLC aren't free. Nothing new. I also bought Sins of a Solar Empire, but somehow had to buy it again when I got some of the expansions. I didn't complain, it's a bit annoying but hey, I ended up with games. Same here... I'm gonna get Titans as soon as I get cash.
However, the first one isn't worth getting if you're planning on getting Titans, because it's included. Just get Titans for the $14CDN or whatever it is. Unless some of the other games grab your fancy.