To be fair, MS admitted to having yield issues as well during their "hot chips" video event, though they have not divulged specifically how it's affecting their projected number of units manufactured by March of 2021. 11 Million units from Sony is about how many PS4 consoles they manufactured in the same amount of time during it's launch. They may need to adjust how many territories they launch in. I think when PS4 launched, it was in North America first and other territories later. They'll get it figured out and in the grand scheme of things, this is a non-issue that nobody will remember a year from now.
Regarding pre-orders, you can still pre-order PS5 at your preferred retailer once it goes live. You're not being forced to pre-order directly from Sony. The invite from Sony doesn't affect that whatsoever. I didn't get an invite either but I don't care. I'm planning to get mine at my local GameStop anyway and trade in my PS4 Pro towards it. I don't know why everyone is in such a tizzy over this. I can't wait for tomorrow's PS5 event to find out more!
Here's some actual good news regarding launch PS5's...
Sony to Use Air Freight to Ensure PS5 Supply Can Meet Demand