There is and was a perfect storm.
1. Winchester stops USA production. Now it’s made in Japan, a lot pricier too.
2. Marlin gets bought by Remington, quality takes a nosedive, people start seeking out anything “JM” stamped.
3. Remington somehow manages to go bankrupt and close due to financial shenanigans, taking Marlin with it.
4. There’s a global pandemic that simultaneously slows or shuts down global supply lines and transport (making those Mirokus, Ubertis, etc much more scarce.)
5. Said pandemic brings with it unrest, which means there are millions of folks who suddenly decide the time is right for a gun. Many probably bought levers, because the humble 30-30 is on about every easily google-able internet list of good value guns. Plus levers are more old timey, less off-putting to many than a new AR or Glock.
6. Said pandemic also brings free stimulus money. Guns are hot commodities. This boosts everything that can go bang.
7. Biden gets elected. Now unrest becomes full on panic as seemingly every gun guy decides to buy what he may ever want since gun-grabbing is in the air. Many decide to buy lever actions since it’s well known (those internet articles again) that levers are very effective, nearly as fast as a semi-auto, and far less likely to be banned. What a great time to buy that Winchester 94 or Marlin 336 you always wanted.
Long story short: lots of folks decided to buy a lever action in the last couple of years as an ideal “just in case” gun, and meanwhile supply of new ones has been very few and far between (except Henry which many look down on.)