1. It is still not the $400 - $600 he is claiming.
2. He said soldered on, which is untrue. Replacement drives will be available during the lifecycle of the machine (iFixit have even said they are planning to release a replacement). If you needed more storage now then you should buy it with more storage. Simple.
3. Great, so the retina model has the screen size you want, discrete graphics like you want, the processors you want, a better screen, faster memory, faster storage. It is called trade offs. If you really can't bring yourself to getting a better machine because you want upgrade the ram after purchase then get a refurb or one from all the stores who still have stock.
The problem is that you guys are acting like you have no options. You do. Life is a constant tradeoff. Pros vs Cons. You can buy a reinta and enjoy all its advantages and deal with the lack of ram upgrades, you can buy a 13inch MacBook Pro and deal with no 15inch screen. You can buy a refurb, buy a stock item from a retailer. Upgrade your current machines further (since that is what you are crying out to do). Or buy another machine.