(OK, I guess the runoff isn't truly instant, but still.)
I worry that this might have the same sort of monotonicity problems as IRV normally does, only in terms of the candidates' ballots instead of the voters'.
Are there real works examples of how such systems operate in practice?
The system is a bit more complex, since it’s for the parliament and you aren’t really voting for parties, but for lists, and the votes get transferred depending on how many seats the list filled, but the basic idea is here.
This actually influenced my voting choice. I went for a more niche party who had little chance to get a seat. I knew that if it didn’t get enough votes to get a seat, my vote wouldn’t go to waste. It would go to the larger party which already has many seats but doesn’t align with my political views as well as the niche one.
It turned out well since the niche party got a seat despite the polling predictions.
Asset Voting seems to be almost unheard of, even among voting reform enthusiasts, despite being over 100 years old and one of the simplest systems out there. Basically it works the same way as a FPTP election, except that after the votes are counted, the losing candidates one by one get to reassign their votes to a remaining candidate.
It doesn't guarantee proportional representation, but it does solve the spoiler problem and doesn't force voters to decide whether to "approve" of a weakly-disliked candidate, or how to rank multiple candidates. The ballot papers wouldn't even have to change their instructions, and it can be easily counted by hand, allowing the votes for each candidate to be placed in their own stack, which makes the process more transparent.