Larger yoyos have become more common. 7075/7068 Alu has become more common. Bimetals have become more common.
All 3 of these contribute to greater stability and increases the ceiling of a yoyos performance.
Undersized yoyos are generally less stable and forgiving. With yoyos becoming better overall, and more companies and yoyos than ever before, the markets become way more competitive so undersized yoyos have become less common because they lack the stability, spin time, and just overall performance
My first post in this thread pretty much sums up how I’ve seen the overall progression of yoyo design The evolution of the yoyo shape