Yes, it seems like ROI in the crypto world assumes everyone should be able to buy a coin for $2 and have it be worth $600 3 years later.
If you can earn 10% per year, that is a very high return. $100k will become $259k in 10 years.
I don't know how much that $2.5 (a number that has been mentioned by someone many times) will be worth in 5 years at PB mining. But, I expect it will be more than $4.03, which is 10% compounded annually for 5 years.
pick any numbers you want and just check the magnitude- year 3,4,5 wont count... ROI in the red can happen from buy conversion or btc value increase- is there a calculator with a derivative for difficulty increases?
Yes it is: https://bitcoinwisdom.com/bitcoin/calculator