Why do sponsors change tours ?

[Taass]

This is something i find realy anoying..

It's no big secret that a gallery that fits the tourpage converts better, so I try to make my galleries to fit the tours.. only if the sponsor then changes the tour i eighter get galleries that burns more bandwith to convert, or a lot of extra work changing the galleries

I'm wondering why not just keep the old tour and then make one more tour.. that would give the option to promote the tour you find converts your trafic best, and even to make more different galleries that still would have high convertions..