A bearing is a bearing is a bearing
Someone somewhere makes them
It's all about quantity and universality
Where possible designers try to design around "stock" bearings available "off the shelf" to keep production costs down
If it's a "special" that's been specified by a designer/engineer
It's quite likely that it's been "made to order" on a limited production run
Hence the exorbitant price
Not forgetting the "mark-up" by various "middle men" (importer/distributor, wholesaler & stockists)
But as GS said "if it ain't broke don't fix it"
100K is not unusual from a bearing which has been properly maintained
Some bearings in large commercial vehicles and ships
Have done 100's of thousands of hours without fuss
So carry on with what you've been doing
It's obviously working