High failure rates after service can only really be technician error.
+1 for following manufacturer guidelines, I service my gear every 100 dives.
This is double talk....the high rate of failure after service is done by the very factory trained people (or at least they are supposed to be) that you are suggesting do the work following manuf guidelines. There is no evidence that regs properly used and cleaned require anywhere near the amount of service that any manufacturer recommends. On the contrary, empirical evidence from people who DIY service suggest a much longer interval is in order. Most anyone who has serviced and maintained mechanical gear are believers in "if it's not broke, don't fix it" philosophy for a good reason- when you do, "fix it" often times you end up introducing problems and at the very least you increase wear and tear and waste money. Wear/time related problems with equipment most often will give indications of future issues. These indications are easily observed, like checking your IP on a regular basis. Diver regulators are simple and very reliable devices and age/use problems usually start very gradually and increase over a fairly long period. Simple IP checks show the early stages of failure, indicating when service is needed. You also have to understand that servicing is a cash cow for dive shops and dive manufs. Service kits that retail for $20-40 are very high profit items with an actual cost of a few dollars. Quality orings purchased in 100 count bags are 2 to 3 cents each, HP seat and filters are a few dollars each- some much less. Simple flow by piston first stages can be completely serviced for less than $1 in parts, same is true for most second stages. Some shops have full time service staff, most do not. Instead, they are owners or sales people who would use reg repair as fill work between customers...ever wonder why it takes several weeks to get a reg serviced when the actual work is an hour or less. I am not suggesting a reg never needs service or that very long intervals are a good idea but every 1 or 2 years, esp on regs that have way less than 100 dives on them is simply not necessary.