If Ludgvan came down would they not need someone to replace them? Slightly unfair as I'm sure penryn would have applied to join Peninsula had that been an option. Also for a team like carharrack who have been told all season that there will be no relegation, to get relegated is also surely not fair, although may do them good. Then you have the plans for combination to reduce the amount of teams in the league, that would have to be scrapped, unless they fancied relegating the bottom 6 clubs.
Probably because of the hard work involved in setting it up & maybe the people who are running it want to see it succeed. If it didn't go ahead where would it leave clubs like Ludgevan, Bude, Penryn, St Day, Carharrack Etc.