I just started to understand Polygon network.

As 1 MATIC = 10^18 Wei and 1 ETH = 10^18 Wei

and Wei is the smallest denomination on both networks, but then

Why is 1 MATIC not equal to 1 ETH (We have 1 ETH ~= 3000 MATIC today).

As both of them have the same Wei as the lowest value and Polygon is based on Ethereum then, logically 1 MATIC == 1 ETH.

Does it not work this way in Crypto currencies or how are the calculations done then, even though both have the same amount of Wei?