In 2015, one AMD Radeon R9 280 video card gave about 6 Ethereum coins per day. Even if I were to sell coins now, it would be millions of dollars. But then no one understood the value of these coins and miners sold them for a few tens of cents or less.
This is why the get-rich-quick 'miner bro' types who just install Nicehash on Windows then immediately sell their coins for fiat $ will lose in the long run. Mining is supposed to be a long-term venture where miners have confidence in the coin and HODL the coin because it's cheaper to mine them than to buy them. It took until 2019 for me to learn that lesson.