With the exception of natural seasonals (which will always be affordable, but could stand to be a little less common) it is impossible for natural pets which can be found all year to have value.
Their names can have value and their stats can have value but the actual natural pet itself never ever will be valuable. There are three hatches a day and no pet more common.
A natural of any species for any player is pretty much guaranteed. Any rarer colour can be traded for endless amounts of naturals and there are so many in play that to remove them would be close to impossible. Not only that, but it would be pointless.
If you want fewer pets in play then you have to cut their production as well as their supply.
For a natural pet to be valuable there has to be something below it. That something would need to be nothing which would require fewer daily hatches and an extremely high chance of hatches failing. I mean literally you would have to be going days and days and days without a successful hatch.
Pet Quest was designed for rarer pets. Anything it has done to sepia through ginger is a bonus.
You all know I want nothing more than a balanced pet market, but valuable naturals is not the right thing to be aiming for.