Dan, by your argument we should all stop flying our 50 year-old airplanes and buy a new SR22. It's obsolete technology, right?
The OP was asking what make practical and economic sense. I think he's heard from several posters that the old generator still has some advantages.
The good news for you is that there ARE FAA approved solid-state replacements for your old magnetos available (SureFly and others). Have you converted your fleet yet? Or are those obsolete mags still getting the job done?
C.
I didn't imply that generators all need to be replaced. I was replying to Snowmass's assertion that the generator was better than the alternator, which it manifestly is not. I could find no advantages to having the generators whatsoever, especially in airplanes that need consistent dispatchability, reliability at night, and good output for night flying when considerable taxiing is involved. Replacing the brushes in an alternator is easy, and if the slip rings need cleaning up it's much easier than cleaning a generator commutator and scraping the insulation down between the segments. Leaving the insulation level eventually causes output loss. Besides that, these things are all getting very old and once a commutator is shot, that's pretty much the end of the line.
Replacing a 50-year-old airplane with a Cirrus doesn't gain much other than a young airframe and huge loan payment and higher insurance costs. It's still full of much the same technology as any old airplane, aside from the electronics.
To me, then, keeping a generator and spending money on it is almost as bad as keeping the vacuum-tube NavCom that came with your 1959 Cessna 172 and spending money keeping it going.
I'm retired and left the fleet work 8 years ago. If there had been a reliable e-Mag and I was still there I'd have certainly considered it. The maintenance time savings alone would have been worthwhile. The reviews on those things at the time were not good, certainly not good enough to consider replacing the mags with them. Things have changed in 8 years. I did install LED landing lights in everything, even back then, long before most people were willing to spring for them. They saved me a lot of hassle replacing incandescent bulbs every few days, and they were ready to go to work at night every time. They used so little current that the light switches never got hot like they could with the incandescents. Saved the switches.
Three years before I left we bought a 172SP with the Garmin G1000. Loved it. It was nice flying it, but not having to fool with the usual gyro hassles was nice too.
I'm not a dinosaur. I was a mechanic, flight instructor and owner of a homebuilt. I can see the cost effectiveness of newer technology and the pitfalls of sticking with old stuff no matter what. There are better ways to do things, and aviation has been a long time catching up. There are still too many archaic items, even on new airplanes, like felt wheel grease seals, something the automakers abandoned 100 years ago. We haven't even gotten to
leather seals yet. Cleveland finally came out with nitrile nosewheel seals, but the mains are still made of felt. They get filthy and let water in. Still using Buna O-rings in hydraulic oleos, when there have been many newer compounds available for a long time that don't harden and shrink in very cold weather and split and let the oil and gas out. And we're still using bias-ply tires. With tubes, yet. And most never get any balancing of any sort, leading to wheel hop and nosewheel shimmy. In such cases, brand-new airplanes are no better than 50-year-old airplanes.