There's a significant segment of Traveller 'players' that are not players at all. They used to be, but life stuff and all that caused them to not have a gaming group any more. So they build things and play with the solo bits of the game. Some people prefer that anyway.
I think T5 might appeal to these people, but as a rule they tend to overlap rather strongly with the people who don't buy anything anymore because they already have their favourite version that's been in use for years or even decades.
This is one thing that makes the size of the Traveller fanbase deceptive. In theory there are loads of fans/potential customers, but many of them won't buy new products for a number of reasons.
To be successful, a new version has to do what the Mongoose Traveller rules did - it has to find a new market.
I can't imagine T5 doing that, for two main reasons.
1. It's an impenetrable morass of tables and rules for making rules for everything
2. It has no associated background sourcebooks
New buyers are likely to want a game that you can pick up and play (and maybe add on bits later) with an interesting setting. T5 in its present form has neither.
So, in reality its main attraction is to a segment of the existing fanbase, most of whom don't buy anything. I see a problem there.
There's also the fact that T5 may never be finished. It's definite-release-date became a joke that ran for so long that nobody finds it funny any more. That's a pretty good indication of how long it's been in the works.
As I've said before, you could create a simple, playable and fun game out of T5 and use the vast mass of other stuff to fuel a ton of supplements, but in its present form it's got very little appeal outside a very small group of diehard fans.