Why do toe nails grow so much slower than finger nails?

It's just the way the body grows them. Genetics and all. There's nothing you can do to change the genetic message sent to your nails to force them to produce keratin at a faster rate. No oils, lotions, potions, vitamins or anything can change genetics.

probably not as exposed to the sun as much ..and things like that

So they don''t make holes in your socks!

Mine grow just as fast as my finger nails. I am always having to cut them. Not easy. My fingernails are hard as diamonds. My toe nails are even harder.