1 - Ever hear of support? Product for free, support for $. Lots of companies solely thrive on this concept of support ( of others products ). They often call it 'professional services'. I suggest you look it up sometime. There is no reason it cant work if you support your own products that you give away.
And Canonical offers that, if fact IIRC it was the first commercial offering Canonical did. But they are not a 'professional services' company, they are a software company with more than a handful of (320+ according to wikipedia I just checked) employees which means they need to, just like every other company, try many avenues to make money to keep those people employed. And quite frankly as a linux admin myself I have (like many of us) a superiority complex that tells me I would never need to purchase support and since I bet we are a no insignificant portion of their user base I'll bet they don't get much money from it. However their music store that is coming, I could spend a few dollars there; or this sync tool so I don't have to screw around with my personal server all the time to make sure my phone sync is working, I could spend a few dollars on that; mainly since I work 8 hours a day on servers and I hate having to come home and waste time fixing servers that could be spent with my children.
2 - Promises from companies have been broken before. Quite often actually. You might want to trust some corporate entity who's directors can change and thus the direction of the company, but i dont.
And who really cares from a Linux vendor? If Shuttleworth comes out tomorrow and says "hey, Ubuntu super pro business edition is now $299.95", the project just forks and carries on with those who disagree.