[varjag]

Nearly all commercial plastics available now were available back in 1997. Even exotic things like PEEK.

The yellowing is due to flame retardant additive to ABS granules. Modern flame resistant ABS stock is prone to same issues.

[simonbarker87]

We use a heat-resistant ABS, 20 years ago it would have yellowed, now it doesn't.

[varjag]

Heat resistant suggests a higher melting point, it is not necessarily flame retardant. The yellowed plastics on old consumer electronics aren't specifically heat resistant.