Bolt should have lost to Gatlin in 2016 as well, Gatlin just tied up badly at the end and lost it.
I'm not a big fan of these athlete woulda / coulda / shoulda to be honest because they usually look at the positive characteristics of the athlete and pretend the negatives don't exist. Bolt has the physical talent to come back and be competitive, but being a sprinter is more than just a pair of legs. Bolt was always lazy, other than 08, 09, and 12 he basically just did enough to get by. In 2011 he likely purposely false started at World's because he knew he hadn't done enough to beat Blake in the 100m.
So yes, Bolt has the physical talent to compete today if he wanted to. But he's also way too lazy, and that's part of the package with him as well, you can't just pretend that doesn't exist.
Jacobs is the worlds fastest man. And if it was measured by top speed, then it might be Noah Lyles.