Also, Idaho is a Republican state, so you naively expect they'd be all rah-rah free market and competition, but this appears to just be pro-big-business and actually quite anti-competitive.
I personally do not think this will have much of an effect on the "startup scene" because the vast majority of the people working at companies that would possibly enforce non-competes such as Micron or HP do not come to work at "startups", because of performance on skills-tests or cultural fit.
I've met a lot of the leadership for various startups in the Treasure Valley, and suing someone over changing employers would be the antithesis of the values they hold, there is one exception I could think of - BlackBox VR (very early stage) somebody leaving them for a competitor could be pretty bad!
I have met startups brag about losing employees to Amazon and Google though.
Nitpick, but: Idaho's largest component of the economy, as well as its largest exports, is technology and not agriculture. It is more of a tech state than an agricultural one.
(Sorry to all Idahoans who don't want this publicized!)