It's important to stress that integrity and authenticity checks wouldn't help in that case. The packages noblesse, genesisbot, aryi, suffer, noblesse2, noblessev2, pytagora, pytagora2 had all valid checksums and really were released by xin1111, suffer, or leonora123. They contain malware because their own developers included it, not because PyPI or one of its mirrors was hacked.

There may be a push in the future for more "guarded" package repositories, à la App Store to today's AUR, probably tying developers' packages to their "real world" identity. There might be an entry fee, to finance the moderation and code review team. It would raise the cost of supply chain attacks, but won't eliminate them: Google Play Store does all that, but it's too juicy a target not to get into anyway. Anything that's popular enough (has as many users as npm or Python) and easy enough to get into (doesn't require an invitation from two Master Masons to publish a package) will get attacked in this way.