As a mildly-disgruntled purchaser of T5, I don't think it was a cash grab at all (although, naturally, I am sure that Marc *hoped* it would be profitable). It was a chance for him to try and use what he thought was a superior core mechanic (not a widely-held opinion) and the ultimate expression of the Traveller-as-coherent-simulator that not only Marc but many players thought they wanted.
It turns out that - on the tabletop - you can have a game or a simulator, and that making the latter actually work (even as framework to build a game upon) took several unpaid people years of additional work.
It turns out that - on the tabletop - you can have a game or a simulator, and that making the latter actually work (even as framework to build a game upon) took several unpaid people years of additional work.