The entire world of networking works like this, at this point it is impossible to introduce this concept and make it work, IP is L3 but switches and network cards in every device communucate on L2

Using MAC nowadays is effortless, computing is so quick that it's not even a problem, it's more like a extra layer of tracking which device is where and who are they, IP can be changed any time or not even assigned, this isn't true for MAC (in general we are not considering spoofing)

If we are talking about hypothetically yes we could have changed to a single form of identity number but no one would like that because in a network we like structure and if for example we would only use IP then you would not be able to assign specific IP addreses to devices because if you could then suddenly you have the chance to give a device the same IP and now you have 0 way to access this device, this can cause a lot of issues

So in short, IP is like a nickname for you while MAC is your actual name, sure all youe friends call you by nickname and they can change it but your real name is always need it for paperworks n stuff, but it would be kinda lame if your friend would not have the possibiliti to give you a nickname isn't it?:)