You do realize of course that many folks cast, size and lube their own bullets for a variety of reasons, or shoot commercially cast fodder for most of the same reasons. Cost, the ability to tailor a load to a gun, tailor a load to a purpose, fun and enjoyment in making your own, accuracy, etc. I realize there are folks who have little to no experience with cast bullets, but stating "prevention is the answer here" is a bit simplistic to say the least.
By the way "clog the riflings" is incorrect. It is rifling not riflings, and the clogging would be more accurately referred to as fouling.
A proper cast load leaves very little to almost no lead fouling. My Super Blackhawk shoots a hard cast 240 grain SWC at 1,400 fps using a less than max load of 2400 with superb accuracy very very light lead fouling. I will usually run some chore boy after 100 to 150 rounds. Even at that point the accuracy is not effected.
One of the best things you can do regarding shooting lead, is to keep it that way. Clean the barrel of any and all copper fouling and don't switch back and forth. Copper has a greater affinity for lead than steel does, and you will find greater lead fouling in a barrel with prior copper fouling, than you will in the same barrel with no copper traces, all else being equal.