Obviously the 90 days solution wouldn't suit everyone, essentially professionals with big studio equipment seem to be less interested in it. It would rather suit the hobbiest, essentially the SE user who are more prone to take their dongle and software around since...well since they have no studio :-)
But I think it would be easy to satisfy both world simply by providing the 90 days method as an option. Originally VSL was probably more "pro-oriented" but, with the introduction of SE which opens to the non-professionals, new solutions need to be found.
I don't honestly believe that insurances are a good solutions: I might be wrong but I believe it wouldn't be that easy to get your money back once your key gets stolen or lost or brakes. It would probably take loads of paper work and time or it would have to be an awfully expensive insurance which would turn out to be totally unconvenient. It's unthinkable for a non-professional to consider this solution which porbably works only if you insure a whole studio. I think this is rather a trick of the sotware company to try to put the blame on the user "well you should have thought about that, you should have insured your software" and try to soften their responsibilitie, but from the practical point of view I don't see this solution working for non-pro costumers...