To clarify, this is a new platform, but they have committed to maintaining the AM5 socket (and supporting platform) through at least some future advancements, as they did with AM4 from Zen, Zen+, Zen 2 and Zen 3.
I think they only committed to 3 years of support, so not as good as AM4's 6(?) years
They never committed to that much support for AM4 either, so I think that's a good sign.