Indeed WHBM. Many USA carriers got themselves into trouble by offering lots of free upgrades to Biz. They did so almost indiscriminately in the belief that pax would see how fantastic the Biz product was, that they would willingly pay for it next time around. Guess what, they didn't.
UK carriers started down this route but then learnt the lesson of social experimentation from across the pond and introduced the rigid rules of pecking order for who gets an upgrade. Yes, there are the occasional exceptions but they are occasional.
Airlines want you to get what you pay for. On the other hand, SJ has had to do lots of give-aways in order to promote the product and get it talked about. In that, they have succeeded. Friends of mine are going to the USA in a week or so and have paid a good price that gets them more than they would have had on the majors for the same price. It is a special holiday for them.
As to whether SJ will pull it off? I remain of the opinion that they started up too late in the economic cycle.