I don't mean to crush the dreams of crypto enthusiasts, but I'm not sure bitcoin reaching $1m is possible, my reason is because the crypto space is filled with thousands of altcoins and some of them have billions of dollars invested in them, bitcoin would easily reach $1m if all the money in altcoins right now are all concentrated on bitcoin alone, however fingers crossed for now, if bitcoin eventually gets to $1m we'll I won't be bother much cause I don't have much bitcoin in my wallet.
Alt will come and go. Almost all are scams or imitators, not decentralized, and with nowhere near the security and infrastructure of BTC. Various alts will come and go, pump and dump etc as BTC's slow but sure momentum continues. Think of BTC as the planet, and then various life-forms coming and going over time, growing on BTC's market cap at the core. We all love to bet on alts, but every cycle the lesson is learned again, and BTC continues to thrive and grow...