It is different by that many zeros. They require much tighter tolerances and higher quality materials. They're also not mass produced.

You can get cheaper laser tubes but there is a difference between them.

That’s debatable. I had a laser cutter for a couple years and used cheap tubes off eBay with zero issues. Cutting power was probably less per watt than with an expensive tube and lifetime was lower, but at 1/4 the price it doesn’t really matter.

You'll have to factor economies of scale, shipping costs, mulitstep glass-blowing steps, and importation duties.

Finally, it's what the market is willing to pay.