After a couple of trips up and down the 'ol garage door I have to think our domestic snails would be a bit tough and stringy. Better a tropical snail that lounged on the beach its whole life.
Amie's question is a good one though...
EDIT -- didn't find anything conclusive in a quick search (other than a complaint from someone who "ordered escargot but was just served a bunch of snails in a styrofoam cup") but it appears to be a function of size. French snails grow relatively large but are very expensive, and there is a large & tasty breed of African snail which grows well in Asia (and is being raised commercially there) but doesn't seem to survive in Canada.
I bet our snails are just too small. There's probably a clever joke to be made but I just don't feel up to it today.