Follow the link in my initial post. The 1,500 Eth minimum is at many sites, including some that are direct quotes from Buterin, such as this one: https://www.ethnews.com/vitalik-buterins-five-steps-to-becoming-a-casper-validator (hint: read Step 3)

I didn't assume that all folks with Eth have technical expertise. Here's what I said: "Folks with that much Ether probably can figure out how to stake it themselves or find someone besides a centralized, hackable exchange to do it."

In terms of pools: Possibly. But, again, go back to my original post. Coinbase can't be a pool operator because they are a money transmitter and are forbidden from doing that. Someone not legally organized in the USA could. Coinbase can't. Plus, Coinbase wouldn't because they are attempting to become a licensed exchange. It would be like NASDAQ creating its own S&P 500 fund to sponsor. They can't do that.