I thought the best properties in Monopoly where the opposite of this? It's my understanding that the best properties in Monopoly are orange followed by green then either red or yellow. Mostly the middle of the road properties. Orange is the best because it's approximately a 7 roll away from jail.
Once you get 6 properties with 4 houses each, you control 75% of all houses.
This is especially true if you play strictly by the rules where you cannot buy a hotel without first having four houses - it's then impossible for anyone to surpass your edge by skipping straight to hotel.
It doesn't matter which group of three, so long as it's cheap enough to build out all the houses quickly.
But yes, orange is best because of jail
The reason I've preferred purple and (dark) blue is that they only require two properties to have a monopoly, so you can get monopolies sooner. It might be confirmation bias on my part, but my memory is that when I get these monopolies early it often prevents people from developing the orange properties. But like I said, I honestly don't know.
You're probably right that in the long run the orange properties would pay off the most based on being ~7 away from jail, but I wonder if games play out long enough for that to outweigh the effects of getting monopolies early.
The results are inevitable at that point.