IN the '60s/70, oil companies were mainly just companies that happened to do things oil-related. After the '84 crash, the character of those companies changed d

IN the '60s/70, oil companies were mainly just companies that happened to do things oil-related. After the '84 crash, the character of those companies changed dramatically. I don't know if that's inherent to that market or just a temporary phenomenon. If it is inherent, then that makes for a barrier to entry.