When they designed the first multisat systems, they really did not know how many satellites they would end up with, or how they would handle stack plan for multiple satellites if they ended up with more. The whole 13v/18v and 22KHz tone system looks foolish today but it was a practical way to solve a difficult problem; there wasn't enough bandwidth on a single cable to accommodate all the channels.. No-one thought putting the guide data with the 119 signals was an issue; again, it solved a difficult problem. When 103 came along, no-one thought having the guide data on 119 was an issue and indeed for most people it wasn't. But for people who wanted HD (which was only on 103 at the start) but did not have line of sight to 119, it caused problems. Even then there were workarounds - on a receiver, autotuning to a 101 channel during the night made sure the guide was refreshed every day. With a DVR, setting to record two 101 channels at the same time just for a few minutes every night solved the problem also. And when the SWM system came along, since the guide is on its own dedicated channel to the receivers they just took it from 101 regardless of the satellite you were watching.
I guess some form of SWM will be around for a while, but who really knows? The arrival of RDBS on DirecTV 14 and 15 will cause some changes, we'll probably all need new LNBs. What's beyond that.........