A very interesting little experiment! Based off this, the author notes that the orange streets will provide a steady stream of income, and this is useful information.
But the trick in Monopoly is to get hotels on your properties as quickly as possible, because this not only provides you with a revenue stream (and fastest return on investment), but also takes money away from your competitors, who would have used it to buy/upgrade their own properties. An important factor is therefore how quickly you can acquire all the streets in a block so you can start putting up hotels, and p * rent of a single street is only one part of that equation.
But the trick in Monopoly is to get hotels on your properties as quickly as possible, because this not only provides you with a revenue stream (and fastest return on investment), but also takes money away from your competitors, who would have used it to buy/upgrade their own properties. An important factor is therefore how quickly you can acquire all the streets in a block so you can start putting up hotels, and p * rent of a single street is only one part of that equation.