Dude, this is awesome.
Because I wrote that.

I know Audiosurf has no official plot, and I agree that it works best without one, but it is fun to use your imagination sometimes.
I made a few addendums in that GameFAQs topic too, but there are still some things to factor in since I discovered the concept of chaining and multiple-color match bonuses.
I guess you get more points for chaining because your air purification machine cools down in between matches, but if you keep it running constantly, it makes for more air profit... And you get more points for matching multiple colors at once because it's like... The two gas pockets together can intermingle during purification and generally yield more for your stores.
Pusher elite gets a 100% bonus on an empty-board match because it is vastly more efficient when it doesn't have to store the unrefined gas in the machine.
White/black blocks, I suppose would be oxygen in a solid form (if such a thing could be...?) and so the air purifier can't process them like the gaseous blocks. And if you have white/black blocks totally blocking off your grid, it's just that. A physical blockage of your air-gathering system.