This is only a question of engineering and can be solved with relative ease. The final question will rest with cost; i.e., if manufacturing costs keep it below the cost of a new USB-C power supply.
1st, pls note the the new magnetic solutions out there is just a magnectic adapter not a Magsafe 1 or 2 to USB-C.
Anyways, what is being asked here is not a big deal, and I always found strange that this still do not exist, sorry I cant remember where I saw it but, apparently the issue here is that Apple has a very strong patent on Magsafe, which protects it to the point that not even adapters can be made, which also explains why only a Magsafe 1 to 2 adapter does exist.
I still dream it will exist one day though, I have plenty Magsafe power packs.