I thought the $100 price was just a wee-bit too high for me. However, when the 30% off sales came around, I took advantage and upgraded both the PODxt as well as both of my HD500s. I have NOT regretted any of the model pack purchases!
So, I guess $100 may be okay, as long as the occasional sale comes up so that we cheapskates get join the club. I did think that the HD upgrade was a bit slim in the offerings as compared to what the XT upgrade included. However, I also understand the extra time and effort that goes into the HD models.
Bottom line: I love the idea that I can buy a software upgrade without having to shell out another $300-$500 for an additional device. If I say upgrades should be free or way under-priced, then Line6 has no real incentive to make the upgrade/expansion effort. Might be nice to have a reward system for previous purchasers of model packs or early adapters/adopters of new hardware. If I buy the Helix at $1500 and a year later the price drops to $1250, it would be nice to get a price break on a model pack upgrade for jumping onboard early. Some responders mentioned an "a la carte" option, where you pay only for the models you want - with a flat rate fee. There's good and bad for that... If an obscure tone doesn't look to be a money maker, L6 might not go ahead and make it. Packaging helps round out the upgrade and might have a few surprises that one might not have considered buying.
Many of the comments have been right on for a capitalist system: the market sets the price. If L6 says $200 for a model pack and no one buys it, then they usually find the sweet spot that entices enough buyers to recoup their investment cost for making the upgrade. For me, the tough part is paying for "electrons." Yeah, R&D costs money, so does maintaining a server network and you gotta pay the employees. So, I get it. I'm just happy that discounts pop up every now and then. And really, the amount of modeled gear you get is waaaay cheaper than buying the actual hardware. The FX Junkie package offered 35 effects for $50. That same $50 might get you two pedals of questionable reliability at a pawn shop. Big picture, $100 ain't bad. Sale prices are the sprinkles on the cupcake of tone.