The question was whether or not the percentage of music show wins captured by the top artists in a given year has trended up or down over time. Let's call this "win concentration".
Now the last thread I created actually contained a listing of the top 5 artists with the most music show wins in each year from 1981 to 2020, so I already had the necessary data to perform this analysis.
Thus, I simply added together the number of wins achieved by the top 5 artists in each year, then divided the result by the total number of wins that year. My calculations are shown below:
And now here are the results, but graphed:
It's obvious that there is a downward trend in the percentage of wins awarded to the top 5 artists each year. My guess is that we see decreased win concentration simply because there are so many artists out there competing these days.
However, the recent successes of groups such as BTS and Twice (who have each won over 100 times) do appear to be opposing the general downward trend, so I'm curious to see if this movement will continue in the future.