Hooper started off bowling medium pace swing I think.
As for the original premise, when I was growing up, every provincial team in NZ had a spinning all rounder at 6 or 7... or two. Chris Kuggeleijn, Evan Gray, Stu Duff, Mark Priest, Vaughan Brown, John Bracewell, Dipak Patel etc. Given NZ pitches through the ages, a spinner who couldn't bat was a real luxury, so they had to be very good to survive (eg, Stephen Boock).
Meanwhile in India, lots of spinners over the years couldn't bat but made the team (Ojha, Raju, Doshi, Hirwani, Prasanna, Bedi, Chandra) while quite a lot of allrounders were seam bowlers, eg Kapil, Prabhakar, Phadkar, Lala Amarnath, Madan Lal, Ghavri, Roger Binny, etc.
As to why there are more top seam allrounders, I think it's just a case of numbers - there are more seam bowlers per team than spinners, so there are more seam allrounders. If you listed out the top 20 allrounders, I suspect more than 5 of them would be spinners, so the basic premise seems wrong - ranking allrounders is obviously subjective but I'd probably have Jadeja, Shakib, Faulkner, Ashwin, Rhodes, Mushtaq, Mankad, Macartney, Benaud in there.