When the Apple Silicon Developer Transition Kit shipped with just USB3, it lead to some speculation over the future of Thunderbolt on the Mac. In a statement to Rene Ritchie, Apple said that at least some Apple Silicon Macs will support Thunderbolt:
Over a decade ago, Apple partnered with Intel to design and develop Thunderbolt, and today our customers enjoy the speed and flexibility it brings to every Mac. We remain committed to the future of Thunderbolt and will support it in Macs with Apple silicon.
With TB4 rationalizing USB-C and Thunderbolt in one cable, with it being the ultimate culmination of differing standards, with Intel abandoning licensing fees, and with Apple being on the standards board, I don’t know who really thought Apple would abandon it, or what they would switch to.