This is what's really going on: YC was bidding too low for companies, and now they're bidding higher so they don't lose out. They did a great job having people not think of it that way.
You say this yourself with “That's $500k for (7% + ?) of the company.”
Bidding higher would mean more money for the same equity or less equity for the same money. That’s not what’s happening here.
To be clear, the new YC standard deal is strictly better than the old one, because you don’t have to take the SAFE. But it’s not dramatically better. For many of us the 7% for $125K remains a nonstarter.
It's not a big mystery what the SAFE valuation cap is going to be. Post-YC valuations are generally $20M+ these days, and having $500k in the bank would presumably make them higher, which means the $375k will convert to 1.875% of the company or less.