Right, but there is a TPM pin-out standard -- so theoretically you could swap out the TPM of any device (which has a physical TPM obviously) with any other manufacturer's TPM and it would still "just work". While it might be implemented in Intel ME, there are a lot of laptops that have physical TPM chips.

Some manufacturers just don't pay more for an LPC or SPI-based TPM, and just use the fTPM one running as an ME applet (my Kaby Lake laptop does this)