I wrote a few lengthier comments on some other similar replies. Summarized my argument is that it seems to me to be strictly better that select defenders have an advantage, rather than everyone being equalized. If you're not one of the privileged few that might be frustrating, but open source models upgrade the attack and defense by the same amount, so open source cyber capabilities being at the frontier only results in a defender disadvantage.

Replying here also as I'm curious about the counterargument.