Steve’s Camera is going to be much more authoritative in regards to parts availability and general serviceability than any of the civilians you are likely to find lurking in camera forums. I had one of the first run of ZI bodies. Whether one likes the camera or not, it was not a sales success and had a relatively short run. So there’s not many of them. There are follow on effects from that, and it’s probably unreasonable to doubt what your service man told you, as that’s pretty much to be expected under the circumstances. The only safeguard would be to buy a parts camera, which is not cost effective in the case of the ZI.
If you like the camera, use it until it doesn’t work any more, probably a long way off, then see if you can get it fixed. Then you’ll know. At this point, anyone not currently in the repair business is just guessing.