Probably because most training occurred in them and people are comfortable with the airframes. I bought my Archer because it would do everything a 182 would do on 2 less cylinders. I have no desire for STOl or big tires for a gravel bar. Toting my fam around comfortably for the best price. Archer had the speed and load for the least cost.
I don't know what you mean by saying 172s/PA28s have training wheels. What makes you thing "anything" is better than those two airframes? Cessna and Piper are still in business. Grumman sold out and then made postal trucks and firetrucks. The planes have little support now, except for scrap yard shopping.
Sadly lots of folks a creatures of habit to a fault.
What I meant by training wheels is that piper and Cessna made those two planes so easy to fly and stable that they had to make sacrifices in other areas.
Who's in business and not in business doesn't always have much to do with the quality of their product, and Grumman made lots of aircraft, many of which are highly regarded by experienced pilots.
I already stated the reasons I believe he AA5, and even AA1, line are better then PA28/172/152/0s, I've flown all of these aircraft, and the grummans just fly better, ground handle better, etc
I also have found the grummans handle more like high performance aircraft in the way they take off and land, I'd say a AA1/5 would transition to a mooney much better than a 172/52 or PA28
As far as me saying it's better because that's what I fly, I have never owned any of the above planes, and none of the above planes are much like my 185, infact if anything following the "it's not what he flys" logic, I should be more of a Cessna fan boy.
The grummans AA5 is better than the 172/PA28, but that's just one working pilot/instructors opinion, worth exactly what you paid for it.
Ether way, go fly the planes you're thinking about, and pick the one you like, I'd wager you'll end up liking how the grummans flys however
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