As I was aware (have not looked for a while) Rotax do engine development for HD as well as selling the stand alone engines they are famous for. So for HD to ditch Buell and MV but not mention Rotax is entirely consistant with HD returning to it's core buisness.
Rotax is also a far lager company than either Buell or MV, making engines for boats, light aircraft, skidoos etc.
So for HD to axe Rotax would be a sign of desperation on their part.
I think they will revive Buell when the time is right.