Doesn't appear on their website anymore, but don't remember hearing anything about them dropping them.
I am assuming that WOTC pulled their licensing agreement.
I have no proof only conjecture.
you can still buy them on amazon for now.
I thought I remembered each license only covering one or two products at a time. So it's not a matter of ditching so much as not continuing.
That's sad to hear. I have their Temple of Elemental Evil release; which included both the original 1E AD&D version, and a version for 5E.
The reboot and expansion of The Dark Tower, which is supposed to be delivered to KS backers next month, is part of this line. They had previously said they were going to do Caverns of Thracia, but with the death of P/J Jaquays, not sure where that's going. And they just had a Grimtooth's Traps thing that I think was associated with the line. So far as I know they haven't announced any other old TSR conversions.
After I get my copy of Dark Tower I'm done with them in any case.
I dunno. I can't really speculate on what their plans were versus the actual sales of these products. I skipped ToEE but got the others before it. Maybe with the waning interest in 5e there isn't much potential for re-doing old adventures for 5e any more.