But, that does not take into account a lot of other variables:
One is that as more miners switch to Bitcoin Cash, the difficulty will increase, making it less profitable.
Two, although minor, is that some minors may politically disagree with Bitcoin Cash due to its radically large block size, and be dis-incentivized to mine it for that reason.
Third, most importantly, is that you cannot sell Bitcoins right after you mine them. You have to wait for a very large amount of confirmations[1]. So if you start mining Bitcoin Cash with all of your resources, then the price crashes, you may end up with large losses, compared to if you had stuck with Bitcoin.
To add information about your question, the amount of bitcoins produced in blocks is very low: 12.5, currently. With a supply over 16.5 million, it barely makes a dent in it unless you give it years.
[1]: https://bitcoin.stackexchange.com/questions/1991/what-is-the... [2]: https://coinmarketcap.com/currencies/bitcoin-cash/