Yes, I also believe that Verizon will cease offering unlimited data plans fairly soon.
I've been with them and AT&T concurrently for over a decade. they're both fairly similar, yet Verizon tends to be a bit more expensive and proprietary.
If you're going to Verizon for an iPhone with unlimited data, I strongly advise you to do it now.
I'm grandfathered into unlimited data with AT&T and I make very good use of it. I could not get by on either of their new plans without going over.