In the early days of Bitcoin like 2011, you could mine basically for free using a gaming PC you already owned (there are a lot of assumptions here that coiners don't want to get into). I actually did this. This has nothing to do with how PoW works today, where even obscure chains are slammed with GPU farms within minutes of mainnet launch.

With PoS you have to buy coins before you can stake. There's no way to bootstrap your stake without spending money.

Because that's how Bitcoin maximalists view Ethereum, and basically all other major alts.