[nabilhat]

A more powerful laser is only half of the equation for cutting metal effectively.

The laser only melts the metal, it doesn't move it out of the cut, and some metals can react in plain air to sputter back at the emitter optics. Gas is forced under pressure at the cut to clear it. With some metals and/or thinner (speaking from a commercial perspective) stock, you can get away with plain air at high volumes of normal air compressor pressures with good results if it's very clean and dry. Others require specifically reactive or nonreactive gases or blends of gases. That's true for most hot cutting processes though. Plasma usually consumes plain air to blow out the cut, oxy-fuel uses excess oxygen to reactively blow out the cut. Lasers with their extremely narrow kerf are more finicky, which can mean a surprisingly high consumables cost.

More powerful lasers also require the optical hardware to operate in a light vacuum. Plasma generated by dust and air itself will ablate expensive parts. Home shops shouldn't need that much power though. If you're cutting thick or difficult metals regularly, that's not a hobby any more.

Then there's the byproducts. Organics get blasted into all kinds of random organic-ish things that aren't great to ingest or emit at ground level near neighbors (PSA, this is true for current hobby lasers). Cutting metals can get really exciting if you don't clean often and thoroughly enough to prevent a critical mass of finely powdered byproducts. An iron or aluminum fire will wreck your laser. An iron and aluminum fire will wreck your laser, and whatever it's sitting on, and the concrete below that.