It's "early" until the sockets and controllers are standard Shenzhen factory pick-and-place jellybeans. For the first few years of USB-C, it was essentially just being supported by one or two suppliers that most factories didn't work with — because that's all that needed to exist in the market when it was only Apple and maybe Intel sticking those chips and sockets on things.
See also: Thunderbolt, which still has this problem even today. (With the move to merging it into "USB4" in large part an attempt to solve the chicken-and-egg board-design-vs-part-supply problem by at least allowing use of the now-jellybean USB-C sockets, thus reducing the problem to "just" one of Thunderbolt-enabled controller-chip sourcing. And having an SoC that speaks PCIe in the first place.)
See also: Thunderbolt, which still has this problem even today. (With the move to merging it into "USB4" in large part an attempt to solve the chicken-and-egg board-design-vs-part-supply problem by at least allowing use of the now-jellybean USB-C sockets, thus reducing the problem to "just" one of Thunderbolt-enabled controller-chip sourcing. And having an SoC that speaks PCIe in the first place.)