Now, with Thunderbolt 4, there is no option for a PC maker. I (and all of our customer support agents) have a great appreciation for Apple making the full implementation a standard on every Mac made.
or even whether an additional add-on card was necessary to use Thunderbolt 3 at all. A PC user needed to look at the small print to know if their system could do 40Gb/s bandwidth, support multiple displays, power delivery, etc…. While Apple has always fully implemented Thunderbolt standards, PC/Windows makers had optionality with what parts and features would be present on a Thunderbolt 3 system.