We don't usually pull on the wire when unplugging, just the connector at the base. If I remember correctly from cleaning the laptop internals, it has a standard DC in jack which is soldered to the system board. I have gone through a total of 2 chargers before this one for different reasons.
For the what happened to the last 2 chargers I have replaced, I replaced the tips as they snapped off oddly (OEM UNITS), but those are VERY hard to find as they are a size "N". Those however, didn't last very long and looked shoddy. So, I bought the one referenced in the link (same style at least), and have had to replace that cord instead of paying for a full charger which can be spendy.
This is the charger we are using
which is why it is so modular.
What I believe happens is the cord gets bent right around that stress point (Arrow on right points to it in the first post picture), but just under, as that stress point is extremely rigid. The last one broke right under it with maybe half a mm of clearance so was unable to do a self repair of soldering.
I have thought about the heat shrink hiding any problems later down the road, so that is why I was asking since yeah, it would be an easy "fix" to cover the connector, but really - I can imagine it still not reinforcing it.
I have read about using a makeshift 'splint' to reinforce the connection, but my theory on this would be fine until you got down to the end of the splint, then you have a new weak point.
Why would I be wanting to put so much effort into a $7/cord? See the first post - Getting a brand new laptop in the very near future and am looking straight ahead at a plausible solution for that one too.