I think Arakon blows the problems out of proportion a bit, but his conclusions are solid - the only way to run Genesis games on SCD is to spend a large amount of effort patching the code for EACH GAME to run from SCD RAM. Genesis games are generally not coded to be easily relocatable; it's not simply a matter of changing one or two variables, you'd have to go through the ROM and alter EVERY instruction that references ROM (except for PC-relative references). It might be possible to write tools to accelerate the process, but it's still not going to happen without a lot of programmer effort, and the rewards are just too small for most people to want to try it - if you want to play Genesis games without the cartridge, the emulators are generally good enough to get the job done.