Just to play devil's advocate, he also stated that he's been away from the Amiga scene for 11 years. Given the way the question was phrased, he might never have heard of OS4. Although MorphOS does seem to be the less expensive way to achieve a NG "Amiga".
In either case, welcome back!
I'll bite.
Would it not be a tad strange for someone away from the scene that long to have heard of MorphOS but not OS4?