Ooh that. So much that!
A lot of it, in my opinion, has to do with demographics, how well known a poster is, the type of project, all that stuff. The fact remains that Ideas is always like the lottery in some ways. I mean, yes, you will always have several thousand projects that will always be at the bottom, and never make it past 100 or even 500. The other three brackets are made up of decent to fantastic projects that never gain much support beyond a small initial push, great projects that gain a lot initially and then trickle (some of these make it to 10k over the years). And then the top bracket which just seems to fly up there instantaneously (whether because of IP fanbase, the power of social media sharing, etc...) Not implying at all that the ones that shoot up are not good projects, there are all different levels of good or bad in all of these brackets.
I think for me the only thing that makes me a bit miffed is when people suggest raising the number of supporters needed as if the above proportions have changed. They haven't entirely. I mean, yes, there are more projects making it to review, but there are also more projects overall being submitted all the time, which means the brackets stay the same, the total population has just increased.
When I first started on Ideas (six years ago I think? I don't know, I'm old) you would possibly have twelve or fourteen projects approved per day that would go onto the pages. And there were days when nothing new would be posted, which did give the newest projects a bit of a boost since they weren't buried on the page for at least a day or so. Currently, there's a whole lot more being approved (I should know, supporting each and every one takes so long in the mornings sometimes! And yes, I'm one of those people, but there's a reason for that I promise). So nowadays it can be as high as forty-five projects in a given day, everything gets buried, and the time span required to get the initial support shrinks rapidly. It's a race to keep the projects from being buried.
That was an extremely long-winded explanation but that's my experience. My only gripe with the raising the requirements is that because more projects make it through, people seem to assume that the top bracket has expanded while the others stay constant or shrink, which is not the case. All brackets are expanding. Like the universe!