It was 3Trillions back in 2021.
No, it wasn't! It peaked at 1.2 trillion, for 19 million coins to be worth 3 trillion it would have needed a price of of more than $150k per coin, and that never happened.
and the introduction of new ways and methods of mining
Yeah, fracking, dredging, lunar mining, and so on!
You can't introduce "new" methods of mining without changing Bitcoin and that would mean the end of it.
It's expected that the market capitalization of Bitcoin is going to be around 10 to 15 trillion by 2030 but it's still too early to predict that how high the market cap will go by then. The Bitcoin is going to get its upcoming halving event in 2024 and the next one after that is expected to be anywhere around 2028, and if we look at the history of Bitcoin then after each halving event the price as well as the market cap of Bitcoin has got quite noticeable growth.
And if we look in pure terms of $, from 2009 till now the market cap has grown in 14 years from 0 (let's say) to $500 billion. Now, to reach 15 trillion in 2030 it would need to grow 30 times more in half that interval, so it would need on average 60 times more investment than previously! Is it still that plausible?
Another factor that could have a considerable impact on bitcoin's market capitalization would be the deflationary nature of Bitcoin, with a maximum supply of 21 million coins, it would manage to influence its value as fewer coins are mined over time.
Bitcoin is not deflationary right now and won't be till 2030 either, the fact that you still have more Bitcoins getting mined every day is clearly a sign of this, you have an
increased supply of coins!