The price difference is largely real, and the efficiency badge is not the thing that varies.
That badge measures efficiency, how much comes out relative to what goes in. It says nothing about voltage stability under load, ripple, the quality of the capacitors, the protections, or whether it will fail gracefully. Two units with the same badge can be very different products, and this is why the badge misleads so many buyers.
What you are paying for at the higher end:
Stable voltage under transient load, which is exactly the shutdown problem above.
Proper protection circuitry, over-current, over-voltage, short circuit: that actually works rather than being listed.
Better components, particularly capacitors, which is most of why one lasts a decade and another dies in three years.
A longer warranty, which is a decent proxy because the manufacturer is pricing their own failure rate.
The practical approach: find out who actually manufactures the unit, since a relatively small number of factories build supplies for many brands, and look for an independent review that measured it on a bench rather than a written overview. A well-reviewed mid-price unit is the sweet spot; the very cheapest tier is where the corners are cut.