I think there are regulations requiring that new products with mains plugs must have them moulded on. I think it's a safety thing; users tend to fit plugs incorrectly, causing fires. I think it's regrettable; the correct remedy would have been to teach kids how to wire a plug correctly. Oh well.
We were taught that in school. I remember it well because we were given a short piece of cable and plug to do it ourselves. Sadly the idiot next to me plugged his in and switched it on whilst the other end of the cable was shorted out.
Turns out it's much easier to fix the plug than fix people.
And the cut off molded ones still end up in a landfill.
And that's my point - in my granddads time, all devices came with plugs that could be repaired and re-used (and my granddad never threw them away) - and today, all devices come with plugs that can only be cut off and thrown away.
I fully believe that the molded ones are actually both cheaper AND more durable (will last longer without needing repair). But they are neither repairable nor reusable, and thus still end up in a landfill sooner than the old ones, when those old ones do get repaired and reused.
And the same is true for most other components of any device.
