Not to belabor the point, but Knifemaking _can_ involve exposure to high temperature molten salt baths (Sodium and Nitrate salts), liquid nitrogen, precise timing, temperature control, and varieties of chemical etchants.

It seems that they probably have similar risks, though glassblowing for the lab might require a broader domain knowledge.

You're talking about knife-making, I'm talking about knife-using. While it may be the case that a knife-maker works with high temperatures and toxic substances, it is not the case for a knife-user. Users of laboratory glassware, on the other hand, are constantly risking exposure to this stuff. They depend on high quality glassware to keep them safe.

The consequences for using a poorly-made Erlenmeyer flask are potentially devastating on a far larger scale than for a poorly-made knife.