Yes, it sure has had a long run! But here's an alternate perspective. Suppose Helix had never existed and Stadium had never been announced. Then Line 6 introduced Helix today, at the post-Stadium price, and it incorporated all the updates we have now. I think it would be very popular, and definitely competitive with what else is out there.
Or, suppose Stadium existed for the past year. Comments in the forum would be "looks really cool, but I don't need the live performance features and it's out of reach of my budget." So then Line 6 announces the Helix. Sure, there's no touch screen and the modeling isn't quite as amazing, but still, at the lower price people are happy to have the soul of a Stadium in a Helix they can afford. Then Line 6 introduces Helix Native, which most certainly can hold its own (to say the least) with AmpliTube, Guitar Rig, and the other amp sims out there.
Again, I don't know Line 6's thinking, but there's nothing wrong - and a lot tha's right - about Helix. It makes sense to have a broader product line with more options for potential customers.