MarkC,
It's a shame that your Marlin stock gave out, but these things DO happen. Better that it happen at the range or while plinkin than when in the field with no tools or backup gun!
As fine a product as Marlin lever actions are (I've owned several of them, and still have a couple), faulty stock fits are not monopolized by Marlin.
A properly fit, crack-free stock, should last indefinitely, even if hot, heavy bullets are fired! I've clocked more than 2,000 rounds from my M1895 .45-70 using factory-duplication loads and HOTTER, with no stock failures.
I've know dozens of Cowboy shooters that fire off hundreds of pounds of lead per year, and stock failure is RARE!.
Why not just re-fit your rifle with a new stock and inspect regularly? It's not likely to happen again.
HTH
John