True, they're not easy to source. Its been awhile but had acquired NOS cartridge type F.A.G. with Delrin housing, Swiss made. Incredible cheap for $15 plus shipping. Ebay seller was in the US with a small stock, English, French, Italian threaded versions. The lock ring wrench can be had for $12 / China made.

Also, but as a steel housing these same bottom brackets are sometimes offered from a Swiss maker Nadex. Not cheap.