Because my dad couldn't keep up with my shooting...
That was almost 20 years ago. And after he got sick of me being at his house all hours of the night loading (I'm a night owl) I got some great deals at estate auctions on reloading equipment and components.
I actually bought a 357 six years ago just because I wanted to learn to load pistol shells. The 9mm came two years ago.
Now I have passed on my limited loading expertise to family, friends, coworkers, and friends of family. Maybe if we reloaders would keep the secrets of the trade to ourselves, reloading components might not be so hard to find!!! But that's just not me.