Apparently, we are having a failure to communicate.
I based my 384MB value on Verizon's posted number. I'd like to know where you got yours. Also, your statement, "... you are only allowed to use 384... The rest is used for the system." doesn't make any sense without at least some clarification.
The "system" is the OS. Either it uses all the RAM or it is kernel-limited to use only 384MB. If I remember correctly, Eclair's kernel was limited to using only 384MB, but that has nothing to do with how much RAM the phone's specs say are in the phone.
As for the update, regardless of how much you are willing to pay for the phone, the fact is that the carrier WILL lock you into a 2 year contract if you opt for saving some money up front as the carrier will NOT discount the monthly price if you pay full retail.
With the Android OS is changing so quickly and so many new features being added (software, not features that affect hardware requirements), it is realistic to expect updates in a timely manner. Especially since the carrier will void your warranty if you have the temerity to be caught customizing it by rooting/custom ROMs.
In addition, it is part of the Google/Android selling points that the phones will be updated with rapid OS updates as new features are added. It is a VERY short term view (which Motorola apparently found out before it hit it big with Android) to make your products obsolete every 6 months AND basically discontinue support for them.
Finally, these phones are being released almost as soon as the hardware is baked, leaving many software bugs to be worked out by we the users. I don't mind being a beta tester, but these are still fairly simple devices, with limited hardware to support, so the basic functions should be worked out before the phone is released. Once the hardware is ready AND the initial software is fully baked, follow up updates to an OS like Android should be basically limited to getting the kernel to work properly and let the OS run on top of it as the OS was designed. Most of the problems I've seen are kernel level stuff (GPS locking, etc.) This isn't rocket science.
While Google would have a tough time with keeping kernels up to date, it shouldn't be NEARLY as big an issue with the hardware manufacturers as part of their design process should be presenting hardware that follows the same basic design principles which would simplify changes to technological advances (CPU, graphics, etc.) as opposed to standard hardware (buttons, battery, etc.). And since many CPU/graphics use the same commands, the changes are not on the level of a complete rewrite of the driver/kernel interface.
Yes, I have been involved with hardware design and software matching in a past life, so I do have some experience with this. However, being a hardware company (Samsung, Motorola, HTC, etc.) doesn't mean you have the experience, or even understand what is needed, to avoid design issues.
Scott