It's not really the wattage that's an issue.
If it ran at 600 volts, it would only be 1 amp.

But at 12v, it's 50 amps of current.
Which is a lot.
And it's not massively peaky/bursty, so it needs to withstand that constantly.
Pretty sure something like 10-15mm² cross section of copper is needed for that, which is a thick cable.

But, this is also a problem that has been solved elsewhere. For whatever reason, manufacturers have settled in a terrible solution.