I don't think that the .22 has killed more deer than he .30-30, not even close, but i have heard that about the poaching.
I think if there were actual numbers out there the results would shock you.
I think the .30-30 is'nt as popular now because of the mentality of needing a magnum for even the smallest game animal.
How about wanting something other than a lever gun or maybe wanting something with more effective range and better ballistics than a flying brick? The simple fact of the matter is there are many non-magnum cartridges out there that are far better than the 30-30.