I have a Maxxyz Compact that I upgraded a few years ago with the retro kit when it was first available. At that time I also had the same concern you voiced (why so much for a SSD drive and back some ram). I spoke with the Martin guys before purchasing. Their response was valid and we purchase the kit. The upgrade took about an hour.
Their response had nothing to do with the hardware. They fully acknowledged that I could go buy the hardware myself. What the $1000 is more for (in addition to the little spent on the hardware) is the new licensing on the new SSD. The new SSD comes with Windows 7 (instead of XP) and the Windows 7 authentic sticker to place next to the old XP sticker. Also, it is worth noting that the Windows 7 is not the typical end user version. It is more of a industrial version that is optimized for their hardware.
Additional question...do you have any wings attached to the Compact? If so, do the update with wings unplugged.
I know there was several firmware updates from 2.4 to 3.4, 3.5 and 3.6. Just be prepared to spend some time catching up. Look for the firmware update instructions on controller support website in file archive. Latest released version for the Compact is 3.60.734.
I’d be interested in what the specialist has to say for your problem. If you are able to continue moving forward (without spending $1000) or if you have to roll back until you purchase the retro fit kit.
Hope this helps,