$5-6k for SFO-MUC in business class is actually the low end of the usual range. While there are occasional sales, they are neither common nor predictable. If you need to fly on specific dates, you'll probably have to either pay in that range, or get creative in your routing. For example, there's currently a $3000 fare SFO-BUD, and a $2900 fare SFO-FRA on SQ (with SFO-JFK on VX). Another option would be to book flight + hotel package on Expedia for $3-4k, but that deal involves primarily ST options rather than *A.