pop riddle 4

In the 90's, I searched for what matters, but I needed to win slow.

In the 80's, I searched for what ties, but I needed the key: tons.

In the 70's, I looked for it all, but I needed the bunkers.

But really, every time I searched, I found the most important thing. What was it?

[Outside research is always allowed on riddles, and is often necessary. If you'd like to guess the answer, please post it in the comments box. If you want a clue, or want me to give you the answer for free, post your request in the comments box.]