Leverguns are cheaper (thinking a used Marlin 30-30 here).
In many cases, a lever action does where other guns would not do because they could not be afforded. So it does that better.
FWIW, yeah, I know about Mosin Nagants. But they're not common around here at all. They do turn up but they're not really used as general purpose/hunting rifles as much as they're toys for rednecks with an extra $100 or for milsurp shooters/collectors.
And I disagree about a semi-auto being more likely to malfunction than a lever. Some of the most reliable designs in history are semi-auto (or even select fire). The AK and the FAL come to mind as extremely reliable semi-auto rifles that many of us are familiar with. Sad to say, but these days you can't really compare the two. On one hand you have semi-auto rifles that are built in some cases from brand new OEM military parts kits. They were designed to work well for years of service in the hands of semi-trained people who are going to do stupid things with them occasionally. They handle it (even the maligned M-16 stands up well to run of the mill stupidity in my experience). On the other side, you have a lever action that was built knowing that the end user will likely not shoot more than thousand rounds through it in the entire life of the rifle.
Which do you think is going to be the most reliable over the longest period of time?