Yes, a design factor in the Marlin lever is that after firing a huge number of rounds (more than you will probably ever fire in your entire life), the parts can wear from camming and create a jam.
I had one for 30 years, and used it alot. Never had a single jam.
Although the factor exists, it is obviously a non-problem in any practical sense, since the Marlin 336 has been continuously made for more than 60 years and its sales are in the millions.
The one time I saw a rifle with this jam, the owner ordered a replacement lifter from Brownells, installed it in about 10 minutes, and fully resolved the problem.
If a shtf situation ever arises, you will have a thousand more pressing things to worry about than the question of whether your Marlin will develop this jam, such as food, water, medicine, shelter, disease, and safety.
The only other time I've heard first hand about this jam, was a friend who had an Marlin 1894, and used it every week in Cowboy shoots or practice for Cowboy shoots. He fired about 2,000 rounds a year, and after 3 years he wore his rifle out.
The Winchester 94 can be a fine rifle, if you don't get a cheap clunker made between about 1964 and 1974. Many people prefer its looks and handling. But, I wouldn't ever let the potential of a "Marlin jam" be a factor that would influence my decision. The Winchesters can wear out too.
Hope this helps.
Mannyrock