Comment by exasperaited

The thing I am referring to is actually mentioned in there -- the true defining event for rail standardisation as a business decision is mentioned here in more detail:

https://en.wikipedia.org/wiki/Track_gauge_in_the_United_Stat...

It was a pretty staggering achievement to switch over with so little disruption, and had such rapid, obvious benefits that it kind of ended the notion that keeping entrenched separate gauges could have any merits that outweighed their disadvantages -- it's really the event that made standard gauge the de facto standard.

Things would have taken a generation longer without it, because this was just a plainly capitalistic decision that proved itself essentially instantly.

(Nearest modern equivalent: iMac having no floppy drive and USB)