In laptops, there aren’t a whole lot of parts that can be standardized. Thinkpads have standard storage (NVMe drives) and half standard RAM (some have soldered or partially soldered RAM). So yeah, they’re fairly standardized. In terms of laptops, so are Dell and HP. But in terms of desktops, where everything can be standard, Dell and HP use a lot of proprietary parts, hence they are the opposite of a Thinkpad in terms of desktop.