Given 900 Bitcoin are mined each day, which currently equates to more than $9,000,000 USD - not including fees. 

But with the current ASIC mining hardware generation, the ROI period is well over 600 days without any diff changes. 

What happened to the 90 day ROI???

Here is an example using the Bitcoin mining calculator from Coinwarz for Bitmain's Antminer S19 pro.

https://www.coinwarz.com/mining/bitcoin/calculator

That said, I'm not sure new miners - trying to mine Bitcoin would ever ROI for capitol costs and on-going operating costs, unless the price drastically increases.

What do you think? 

Change my mind.

Cheers!