There is a certain "magnumitis" for one thing, the idea that bigger is always better. There was mention of the 30 or 32 calibers, an let me point out that they too are mostly orphans. I love the 32/20, and even the 32 H&R, but they never caught on. The 327 Mag was another attempt to upgrade the little guns, but was largely stomped on by the 357 guys. In fact, there is pretty much nothing between the 22mag and the 357. I think there are a lot of guns that are sold, fulfill someones fantasy, and set forever in a drawer. They are never really used , so their utility is mostly on paper. The fix is in so to speak, as anything that does not meet the "self defense round" criteria is somehow useless, when in fact it is exactly the opposite. Maybe one round in a million is actually used in a self defense situation vs the BILLIONS of 22 LR rounds fired. A sub-35 caliber handgun/ rifle makes very good sense, very practical. Unfortunately, most firearms are sold for , as I said before, fantasies , not practical utility. When I was young I thought that the 22 mag had to be the most worthless round ever invented. Later in life, a synthetic stocked stainless steel 22mag became the most used firearm I owned for 20 years, until my grandson really really "needed" it.
Now that niche is at present co-occupied by a Hornet and a 357 Handi Rifle. There is a lot of space between a 34 gr Hornet @2850fps and a 140gr JHP @ 1650. I share your sentiment entirely, when the little Marlin CL's in 25/20 and 32/20 came out in the 80's I was in no financial shape to pick one up, I always regret that. I wish they had more to offer. Maybe someday someone will realize that you don't have to go to the grocery store in an F350 dually, and that just because you don't, it doesn't mean you want a PRIUS.