There are several issues with your argument.

First, the highest stakers voting is a very flawed system but it is what we have. Honestly, it's not that different from web2 games when the company listens to the big spenders over the f2p or small spenders. Just because someone has more SPS doesn't mean they are right and many times they vote for their own interest over the interest of the whole community.

Second, this issue is not a DAO matter which means SPS stake is irrelevant. The team may choose to listen to us of these matters but this isn't an actual proposal. This is a way to see how the community feels to show Matt and team so that they make a decision which may or may not influence it.

Third, in this specific situation, not only SPS stake doesn't matter, it's quite the opposite: anyone who's playing with mostly maxed cards and is/was already playing in Diamond/Champion is unaffected. Why are we listening to those players? I am one of them. I didn't feel any difference from this change (only from the 20 flat rating per win/loss). We need to listen to the affected players.

Fourth, you say that there is disconnect between the vocal minority and their stake. Ignoring the stake part, it's true that sometimes vocal minorities make a lot of noise because the people who are happy or somewhat neutral won't write about it as much and people who are unhappy. However, changes are usually taken badly at first and the complaining tends to go down over time as people adapt. It has been the opposite. There are some voices raised at the time but many people gave it time. Matt said that it should take 1 or 2 seasons for things to find an equilibrium. I don't know how many seasons it has been but it's much more than 2 and no equilibrium was found and disagreement voices have only increased. Not only that but there have been many players who have left the game recently, many because of the removal of the leagues, at least partly.

Fifth, this doesn't affect only bronze and silver players. Gold players are probably even more affected. Gold level cards are usually a bit over half the BCX of a max card. That means gold players are about half as invested as diamond players in terms of cards. That's pretty significant. However, to be "forced" to make the sudden change, it's not easy. They will need to buy cards either 1 by 1 (more expensive), find good deals on lower than gold level cards (will probably take time), bite the bullet and buy a max card and try to sell the gold level card, or combine 2 gold level cards going over the max bcx. All of these are not ideal. It's one thing to be able to do it slowly and eventually move up. I didn't start as a max level player. I played with level 1 cards and mostly ghost cards for a long time. I only started leveling up when CL was released and it was a slow process. I played in all the leagues. If there weren't those steps I probably would have never gotten past level 1 and ghost cards.

Sixth, there aren't even 5000 total players.

With all this in mind, even just looking at number of votes, you have to take into account that many (you included) are voting this was because it is Matt's vision. Blind support doesn't mean anything. Any leader wants real feedback not someone who will repeat whatever they say. That has no value. Also, many who would have voted to bring back leagues have left the game because of this change.

I think more important than the votes is looking at the comments. Most of them are from affected people who are commenting respectfully and without anger that they want leagues back without leaderboards.