2700 USD would give you a pretty serious Doepfer rig. But yeah, Eurorack’s also getting more expensive, but that’s with the addition of digital modules, screens, etc. Mannequins seems awfully specialized and are hardly the only game in town. Your buying choices are more limited in 4u and if you’re getting new, complete products, you’re also factoring in exchange rates, etc.
Let’s put it this way: the new dual PCO module costs 812 Euro - god, I hope that includes VAT - and that’s 984.67 USD today. Does that sound like what you’d pay for a Eurorack equivalent?