I'm trying to break your post down to manageable pieces, so here goes:

a) Airlines are ultra-competitive now, and they don't want to risk losing your business to a low-cost carrier. For any delay that they are responsible for (mechanical, pilot rest time), they will at a minimum provide food and shelter in a hotel for you. With Star Alliance, they can also have many more options to rebook you on "friendly" airlines. Also, there is now "On My Way" priority remedies in the event of irregular operations (useful in the winter).

b) As for your upcoming vacation, it sounds like you are trying to book for July 2011. Way too early! You'll start seeing deals in May on ac.com for "WebSaver Fares" that will be alot better than what you see now. The Toronto - LAS fares are always kept in check because of the competition from WJ and SunWing; I don't know if YUL has similar competition.

...and you aren't scamming AC. Just as they try to set prices to maximize their profit, you can change your origin to minimize your cost. It all comes to down to how much you value your vacation time (i.e. the cost - time & money - of positioning yourself in LGA vs the amount saved)