I don't know why they don't use magnets to simulate tracker touch (in association with normally sprung keys). A small magnet in each key with a steel strip directly above.
There are systems which use various devices, including magnets, to attempt to simulate tracker touch. Both the examples I'm thinking of are by German builders. As far as I recall, on their websites both appeared to be of good engineering design and high build quality but were also expensive, at least by average amateur standards. One of the makes is, or was, occasionally fitted by at least one UK builder of high quality consoles where tracker touch was requested.
There are other designs, some less expensive, others more so. When I was looking into this a few years ago a big difficulty I had was finding working examples to try out, or finding organists with experience of them who could give reliable and informed opinions. From the little I could gather at the time though, and considering the cost involved, it would seem that trying before buying would be strongly recommended; indeed essential if expensive disappointment were to be avoided.
If you care to send me a PM I will forward some web links. Typing “Tracker touch organ keyboards” into an internet search should also bring up a few references.