I think it solves nothing, cause it's not primarily a XZ issue itself, but some bad actors that infiltrate into the community for years to finally use his credibility to upload a backdoor. Every single package is vulnerable to this kind of attack and has little we can do to completely avoid it
Of course we have to make the best moves to prevent this happening again, however it's not a simple "I'll use X instead of Z" (see what I did here?!), cause both X and Z may be doomed with this shit anytime