It certainly would but it wouldn't be in the spirit of competition. If fans are happy for their club to be nothing more than a side show then fair enough.
The 'costs' shouldn't be significantly different, change the number seven for a more experienced rider (remember that the Premiership ave is to be reduced to 42) and that's it.
They don't have the option, all clubs have agreed to commit to the new set-up.
Of course there's 'little difference' that's why they have a promotion/relegation play-off at the end of the season and the 50 point team building level will be reduced to 42 after the first averages.
I remember Eric Boothroyd saying that Alan Hunt (who he rode with at one time) was his favourite rider. Briggo once said the same about Crutcher, he was tipped to be a World Champion but didn't seem to ride for long. I'm sure many of us saw the other names you featured.
I'm not sure there are any at the moment, the old two year limit on doubling up has been scrapped to increase rider availability. Priority is given to the parent club or the first signed club, in the event of a fixture clash. Trebling up riders usually prioritise the upper league.