You don't need to define good in an absolute sense to see how one thing can be better than another. The flaws of an MCG or LCG are easily witnessed, so it's to

You don't need to define good in an absolute sense to see how one thing can be better than another. The flaws of an MCG or LCG are easily witnessed, so it's totally fair for someone to go find out if it's possible to do better (i.e. remove obvious patterns, fix low period of low order bits, improve statistical quality) without sacrificing much performance; and indeed perhaps making it faster than a large-state LCG of comparable quality would be. If you admit that there are any legitimate uses for non-cryptographic PRNGs then I guess a 32 bit MCG (or "42") is just perfect for you (otherwise you'd know what's better and you don't need to ask anyone to define good). You're easy to please. If you think there are no legitimate use cases for these fast generators at all, then I'm sorry but a lot of people disagree and they will never rewrite their sims, noise generators, world generators, etcetra to use a CSPRNG no matter how much you whine about it.