For years electricians made large diameter holes in electrical boxes with knockout sets that were either manually cranked by a ratchet or hydraulically powered with a hand pump, hose and a lot of fussing. In recent years battery powered Knockouts have become much more popular because they are way more productive but a good GreenLee or Milwaukee tool set (even without any punch or dies) will put you back around $1300.
No questions these are the fastest best option for high volume production but are a bit pricy for some to justify. We’ve seen the Mechanical Knockout tools growing in popularity in the last few years because if offers performance similar to the cordless/hydraulic tools at a much lower cost. The Current Mechanical Knockout 163 ($549) is pretty attractive and with the full 2” set Mechanical Knockout 162PM is only $779.