I don’t know whether or when ENT will be released on Blu-Ray, but clearly it’s a different kind of thing than TNG-R. TNG-R is for Paramount a major project, and for fans a chance to “See it like you’ve never seen it before.”
ENT on Blu-Ray is a much less compelling product: “See it very much like you’ve seen it before, but the image is a little sharper.” Those who want ENT on disc can get it on DVD; videophiles who spurn DVD as a primitive technology can get ENT-HD from digital download or streaming services. I don’t see a BluRay release giving Paramount access to a lot of consumers they can’t sell to today.
If you want disc-traditional special features and an HD image, you can’t get them both in a single product today. If you’re a typical consumer, you’ll make your choice between available formats and Paramount gets their sale. If HD and special features both are important to you, then maybe you’ll be dissuaded from buying, or maybe you’ll choose which is more important to you and buy the format that offers it, or maybe you’ll even be driven to buy it twice so you can have it both ways! The impact of BluRay availability on total sales is unclear, but probably not very large, and possibly not even positive.
On the other hand, it’s a much lesser project for Paramount. Small investment, small risk, small reward. A completely different set of considerations from TNG-R.