On of the consequences of those provisions is often either
1. Companies do weird divisions to keep under the limits
2. Companies are artificially restricted in their growth as they need to add employees but are unable to, for example if the cut of was 50 employees, adding the 49th employee is easy, adding the 50th employee is $$$$$ thus it will not happen, this would mean few companies grow to 50, rather you would see several 50+ employee companies merge as the cost burden for the new 100 employee company would spread over all 100 employees, vs the regulatory cost being hit with the single employee add
IMHO, the US should have much more "larger than X" laws (and clauses that enfold organized subcontractors working for larger corporations).