I think that loss leading leads to device or producer lock in (as it's intended to) and limited the utility of devices for frivolous reasons - if your nuclear reactor specifically requires rods with little notches at the end feel free to warn and protect against incompatible notches, but if that notch requirement was to lock the consumer into your Atomizer Brand Rods(R) then you may force a consumer into making fiscally unsound choices down the line, preventing a new competitor with a genuinely improved (possibly even safer) product from being able to compete fairly. Loss leading is just another barrier to entry that incumbent companies can establish to prevent free competition.

I feel like that's more the Gilette/HP "expensive propriatery consumables" model, not the classic loss leader.

When I think of "loss leader" I think of the Thrifty pharmacies that used to have an ice-cream counter. People went in for a 35-cent cone and ended up buying $10 of other merchandise that more than made up for the 15 cents Thrifty lost on the cone.

That Gilette/HP model is something I consider unethical as well. It's manipulative (instead of a honest deal, it tries to mess up people's calculus), anticompetitive (undercuts honest dealers) and generates ridiculous amounts of waste - doubly so, when you end up in situations like people buying new printers every time their old ones run dry, because even with reduced-capacity starter cartridges, it's still a better deal than just buying ink cartridges.

The example that comes to my mind for "loss leader" is stores a while back selling CD-R spindles for almost free, limit one per customer, to get people in the door. No lock-in at all, just a way of doing advertising.