Their first statement was support through 2025, have they promised something more since then?
AM4 has been introduced in March 2017, the last CPU was released March 2022 (5800x3d) and there are rumors that more AM4 are (rumour) still in development
https://www.techspot.com/news/100839-amd-may-prepping-new-am4-processors-3d-v.html
So it’s likely that AM5 will at least last 5 years, if not longer
AM4 was released in 2016 and started with support for CPUs before Zen 1.
Also, the last CPU released for it was the 5600X3D which was this year.
When they released it they said they’re guaranteeing support for 3 years, but are aiming for 5+ years.
AM3 was supported for 6 years, AM4 has been supported for 7 years and they’re still releasing new CPUs for it. So while past performance doesn’t guarantee anything, they do have a good track record.