Look up the percentage of current postdocs that will receive a tenure track position at a major research university. Then cut that number in half after 5 more years of ridiculous grind as an assistant prof. You're looking at less than 20% chance even if you're willing to move to bumfuck. If you have location restrictions or higher standards on university (which impacts e.g. the amount of funding you can realistically get), it's approaching low single digits in most fields.

Modern academic science is really its own special breed, and unfortunately a lot of that grinding these days goes to fighting the crazy career ladder, not so much directly to obsessive, curious science.