I have always wondered about the bussines model of these free tunnel providers. In tha case of SixXs it was clear: there was no bussines model, it was just idealism. And the end was not all that unpredictable: they (Jeroen Massar and Pim van Pelt) just got tired of it.
In the case of he.net the bussines model was spreading IPv6 so that they could make money on those needing help getting their bussines running on IPv6. There are indications that their free tunnels may not last forever.
Route48? Frankly I know very little about them. But whatever their bussines model was, it apparently didn't work...
It would be a nice day when these tunnel provider were no longer needed because we all could get native IPv6 from our regular ISP.