My OE one lasted reasonably well (14 years), but the bike's under cover at both ends of my usual journey, so has an easier life than yours by the sounds of it. I did try an aftermarket one, but that failed within a few months from corrosion and the spring inside being too feeble... I kept repairing it but recently gave up and replaced it with a second-hand genuine one off ebay.
I was going to attempt to make a solid-state replacement using a magnet embedded in the lever, but decided it was more hassle than it was worth to develop.
