I think you are wrong about that. Apple shipped the iMac starting with USB v1.1 in 1998 [1]. It was the first Mac with a USB port. USB was developed in 1994 from a group of seven companies Compaq, DEC, IBM, Intel, Microsoft, NEC and Nortel. [2] Windows 95 that was released in 1997 had built-in support for USB devices.[3] The market share of Mac at that time was about 4.6% [4]. So no Apple wasn't the first computer to ship with USB support nor was it the reason USB went mainstream.
“Few USB devices made it to market until USB 1.1, released in August 1998, which fixed problems identified in 1.0, mostly relating to hubs. 1.1 was the earliest revision to be widely adopted.”
The iMac G3 was released in August 1998. I didn’t say the iMac was the first computer to have USB ports, because it probably wasn’t quite the first (although, interestingly, no other computer comes up when you try to Google this); importantly, though, it only had USB ports, and killed off ADB, serial, parallel, and SCSI, forcing users to start buying USB peripherals. My family had to get a serial to USB adapter that still worked with OS X the last time I tried it with a GPS receiver (I just looked it up and it may have finally stopped working with Mountain Lion, nearly 15 years later). It was, what, about ten years after that that most PCs finally stopped including PS/2, serial, and parallel ports?
Someone complains that Apple promoted FireWire and was late to support USB 2.0, but FireWire came out first and was technically superior (although some devices do have weird compatibility issues), and that Apple dragged its feet supporting USB 3.0 because they were trying to promote Thunderbolt, but I believe this was because Apple is using Intel chipsets (because Intel killed off Nvidia’s chipsets) and Intel was doing exactly what this person accused Apple of doing.
USB was around long before Apple stopped providing PS/2.
If you buy a phone or tablet from anyone that isn't Apple you will very likely get a USB port. If you buy Apple you will not. Trying to argue that Apple is somehow looking to the future by providing a serial bus years after it was the norm is hard to comprehend.
[1]http://www.everymac.com/systems/apple/imac/specs/imac_ab.htm...
[2]http://en.wikipedia.org/wiki/Universal_Serial_Bus#History
[3] http://en.wikipedia.org/wiki/Windows_95#Editions
[4] http://pctimeline.info/windows/win1997.htm