The problem is that sometimes it IS expensive to implement some feature.
so you have the choice of either having the feature available as an option, or not having it available at all.
Distros are not supposed to just enable every possible option, they are supposed to be selecting a reasonable set of options. Sometimes this means that they provide multiple kernels for you to choose from. Sometimes this means that to get some specific option that's got a particularly high cost for those that don't care about it, you have to compile your own kernel (and the distros that strongly discourage this really should be slapped, and yes, I am thinking of RHEL)
You also sometimes have options that the distro decides are probably important enough to enough people that they are going to make them be the default, and if you don't want to pay the cost of that feature, you will need to compile a kernel without it (again, if the distro doesn't offer an option)
In recent years Distros have in many cases been going too far in just enabling everything "because someone may want it" without considering, or testing the impact of the options.
upstream could be better in figuring out and communicating what the expected impact of options are, but that doesn't help if the Distros don't pay attention.