Why would I ever use an alternate L1 once the Ethereum upgrades finish?

The one thing holding Ethereum back is the fees/throughput. Once these Ethereum upgrades are complete there is literally no reason no use other L1s.

People saying things like "ETH 2.0 will never come out" are just saying shit so they can pump their own doomed to fail shitcoins. Most of these "Ethereum killers" have never remained relevant past one bull market.

It's like everyone who said LTC, BCH, or NANO will surpass BTC because BTC fees are too high/BTC can't scale. Decentralization is the name of the game. Security matters. If I didn't care about decentralization I'd just use a normal database. Anyone can get [insert X] TPS on one environment ,claim its the "future of blockchain", and dump 50% of the tokens on retail.

Once Ethereum comes out in full form it is the end for 99% of L1s. Any real innovation will basically take place on L2s. Why would I use a more unsecure new blockchain platform when I can use Ethereum or an L2 with much better uptime/security?

The only real L1s I see surviving are novel ones like ones focused on privacy, etc.