Keen observation, but you’re getting some important details wrong.
Peter Pan cost 4 million dollars.
The Princess and the Frog cost 105 million dollars.
On the contrary, Disney’s old films were VERY cheap compared to the ones of today. The modern Disney thinks that you can make a good movie by throwing money at it, rather than getting some talented artists and letting them do their thing without executive intervention.
Sorry, but your theory is now dead.