Which is particularly relevant at consultancies where the product is a service.
If you join a consultancy group, and 2 months later quit with the client roster... is it really OK to poach all their clients to start your own consultancy?
All of these contracts are time limited, FWIW. E.g. non-solicitation doesn't mean you can never work your your colleagues again. It protects against someone leaving and then immediately poaching all employees within 12 months. After 12 months you're welcome to poach as much as you'd like.
Edit: Furthermore, non-solicits don't ban your colleagues from quitting with you, as long as you're not directly asking them to quit. If they make the decision independently without being lobbied by a former employee, it's not in violation of non-solicit.
It's true that multiple people can quit at the same time, but non-solicitation clauses significantly impedes the process otherwise companies wouldn't bother to write the them. If you have worked for a shitty company, what delays quitting? Often team loyalty is a big part of that. I think it would massively speed up the decomposition of bad workplaces if entire teams could move in one go. It would be highly efficient for the acquiring company as they get a complete team that already works together, for only slightly more effort than hiring a single employee. It would also be huge disincentive to tolerating bad managers.