It's an outdated but well entrenched model
Any service that can out do them in receiving money, sending money and converting money will win out in time.
We just need a full service business to get it started but 2/3 on the edge is a good start.
An "outdated but well entrenched model" is accurate:
Founded Rochester, New York, U.S.
(1851; 165 years ago)
...Western Union bought out smaller companies rapidly, and by 1860 its lines reached from the East Coast to the Mississippi River, and from the Great Lakes to the Ohio River. In 1861 it opened the first transcontinental telegraph.
IMO, They do not belong in the modern world, but they still employ ~7,000 people.