FireWire, all speeds: was always coupled with USB or other tech that possibly didn’t carry data as fast as FW, but was “good enough” for lots of things. FireWire never really took off aside from digital video cameras, and that got phased out over time, too. DisplayPort: nope.
Compare that to the original iMac, which dropped the serial and SCSI port. People gasped, but in not too long (at least now, looking back in it), USB was everywhere.
And now USB-C. Would it have been as popular as it currently is - on lots of chrome books, many phones, even the Nintendo switch - if Apple has not been so gung ho on it? Possibly, but a bit of me doubts it.