[quote=walterwhite]You can lose your capial in a bank. Put 10000 and leave it there 30 years and see what happens[/quote]
You’ll have at least $10000. So, yes, you’ll have all of your capital. Your buying power might reduce due to inflation, but you won’t lose any $ you put in. You can with gold, depending on when you buy. I.E. if you buy in 1980, you’d be negative nominally for 20+ years. You’d still be negative inflation adjusted today.