I think this is a crucial point as to why for most teams in our division a good season is a ‘now or never’ opportunity to get promoted.
The only clubs, in my opinion, who have a real chance to ‘build towards’ promotion are those like Luton.
I say this as, when they have a good season, for some reason (snobbery?) others see this as being despite having no decent players instead of because they do.
This enables them to add to what they already have as against, like you say, having to constantly start again.