Three letters: L E D
Because GM for a long time was the only make using the actual headlights as DRL"s thus the headlight was on everytime you drove the car .
Some have blamed the 3157 OEM bulb as not being able to handle a 14V spike and causes it to burn out prematurely. But then why does the SOCKET for the bulb wind up being burned to the point that new bulbs cannot be securely plugged in? There is a defect in the lighting system and just replacing the bulbs and the sockets does nothing to fix the problem of voltage spikes.
I like the posting earlier, "If GM/Chevy can’t fix this problem or does not care to, then what else are they “Not worried about?”
How about what appear to me to be dwarf brake rotors on many of the large GMC SUVs?
Perhaps it’s just an illusion.
Because it’s likely two different issues. A voltage spike may cause a lamp to fail but it’s not causing the connector to melt. That’s due to long term power issues such as insufficient conductor or pin sizing, oxidation of the pins or loss of spring tension in the pins.
as the owner of a 2000 GMC Sierra, I can confirm that one of my DRL is currently out. 
I agree with Twin-Turbo.Melting connectors is a sign of long term overloading. Given the massive amount of wiring in modern cars I can understand why they have to downsize thing but it does cause a problem.
Ford had some issues many years ago with their ICRM modules. The module was not the problem. It was the tiny pins in the connector plug and when high amp components like fuel pumps, radiators fans, and so on are routed through them at some point they’re going to cave.
I don’t think it is overloading, I think there is not enough ability to dissipate heat created by the bulb.