It's not a transparency issue, this dark pattern exists everywhere. You advertise "New X starting at $x" which is low enough to attract customers. But the thing you sell for $x is actually lacking in some small but important capacity making it unattractive for actual use. Then you sell an upgrade for the target price and customers are more willing to pay because it feels like they're paying a small premium for the thing they want.

It's a neat psychology trick. Customers are far more receptive to upsells when they're the one doing the upselling.

Where do you think the 'switch' is in that? At what point do they switch something from what was previously offered to something not expected? I don't think there is any switch. The specs are presented as up-front as any hardware spec is.

The switch is that you're some way through the "funnel" before you discover that to get a decent spec machine you need to spend a lot of money. It's the "power of commitment" sales trick.

I don't agree - it says how much storage each version comes with up front in large font on the marketing page https://www.apple.com/mac-pro/specs/. It even lists the 256GB SSD option first, as the default option.

Your assumption requires that no one actually wants or will buy the 256gb option. I for one definitely would consider it, all my current computers have only 256gb and I haven't had issues (external hard drives are cheap).