USB veresus FIREWIRE?

I believe the main reason is that many years ago Apple (which developed Firewire) demanded a royalty for it, on a per use basis, which Intel and the computer motherboard manufacturers considered to be excessive. Therefore Intel designed USB capability into its chipsets, and the rest is history.

Although Firewire continues to be extensively used in some applications, video editing being one example.

Regards,
-- Al

Apple always pretty much demands a premium royalty for pretty much anything in the domain that only it controls.

And they usually get it, which means they are doing something right, namely keeping things as simple yet usable as possible for the masses. That's the Apple business model which works well. Most people do not want to have to make technical decision on their own. Apple makes more of them for you than any of their competitors, but for a premium.

Companies are fighting for every penny. Change in video
ports is an example. My wife used few company laptops over
the years and every time port needed new adapter to connect
to monitor. Ports are often the same but name and connector
changed to avoid paying fees. It happens everywhere.
Helvetica and Switzerland (and many other names) are exactly
the same font with different name to avoid paying (font
cannot be registered but name can).

Apple killed Firewire in Ipods being afraid that they can be
forbidden in large companies (very bad publicity) since they
could be used for hacking of company systems having Direct
Memory Access as a part of Firewire definition (potentially
being able to bypass passwords).

USB is a Peripheral bus that has a lot of overhead running
under protocol at about half of advertised speed engaging
computer's main processor in transactions. Firewire is an
Expansion bus that runs at full speed (guaranteed bandwidth
made it popular in broadcasting) without engaging main
processor.
I use external Firewire Hard Drives with my MacMini (equiped
with Firewire connector) for music playback.