Given that all of them are all powered hubs so power won’t be the issue and you have enough space to put them. How much will it impact performance, latency or other things I don’t know about? Or it will straight up kill the port if there are too many hubs?
Probably the port on your laptop was on a hub built onto the mobo. If my understanding is right that’s how USB ports usually are connected: controller->hub->ports. If you open up device manager and go to USB controllers you’ll see several root hubs and hubs even when you have no external hubs or docks connected.