I'm going to totally, but respectfully disagree. Lead started going out years ago. My dad taught me the fine art of leading when starting when I was around 12 or 13, and I did it for a number of years. With the new fillers, and ones learning how to properly work metal on the older cars, plus the hazards of lead in both the manufacturing side, and retail side, it is dying out. It's so much easier to grab a can of filler and a tube of activator to fix what is wrong, to most people, than it is to do the job properly.
If lead WAS making a comeback, then almost every automotive show on the tube would show how to properly do it. Plus for a lot of people, it just isn't cost effective or practical to use lead. You need to have the torch, gas, paddles, beeswax, acid, solder, flux, and above all "knowledge" to use lead.
Don't get me wrong, there are ones that still go "old school" and do it the way it used to be done, or if they are going for a concours restoration, will still use lead, and some may be wanting to try their hand at it, so they will get in touch with Eastwood's and pick up the materials, but to say that it is coming back.......ain't gonna happen. Even the fillers of a few years back, are constantly getting reformulated to make them safer. With EPA restrictions on everything anymore, lead can only be made so safe. That is why faucets in your house, some solders, and countless other items or being made lead free, or close to lead free.
The true die hard, old school, lead slingers are close to nothing compared to the ones using the new polyester fillers we have today. Safety, convenience, cost, disposal, are all factored in too. You get caught throwing a few pounds of lead dust into a waste site, and it will be someone's ***.