If people would need it, then it would be already deployed. But if the game is not about having "any working testnet5", but "the testnet5, included into Bitcoin Core", then some people are just using Signet, and others are just waiting, to break yet another testnet, and discourage developers from using it for the actual testing.
Lol, Testnet is needed and in a bad way.
Also, an easy way to get massive amounts of Testnet is encouraging for Developers to actually test with Testnet functioning globally and interacting with others.
This helps with transparency of what is to come, if you watch Testnet... which major Bitcoiners all should to an extent.
It'll be included in the next or the Bitcoin Core update after that... It's fairly simple.
I expect a fun Christmas.