Why is operator!= removed in C++20 for many standard library types?

Question

According to cppreference, std::type_info::operator!= gets removed with C++20, however, std::type_info::operator== apparently remains.

What

Answer 1

We don't need a library provided operator!= anymore. Providing operator== allows the compiler to do some juggling and evaluate a != b in terms of a == b, all on its own.

[over.match.oper]

3 For a unary operator @ with an operand of a type whose cv-unqualified version is T1, and for a binary operator @ with a left operand of a type whose cv-unqualified version is T1 and a right operand of a type whose cv-unqualified version is T2, four sets of candidate functions, designated member candidates, non-member candidates, built-in candidates, and rewritten candidates, are constructed as follows:

3.4.3 For the != operator ([expr.eq]), the rewritten candidates include all non-rewritten candidates for the expression x == y.

std::type_info and many more library types had their operator!= removed as part of P1614 - The Mothership has Landed.