I think the easiest way to think of standard promoted after January is that if you have a 5% promoted rate, you can expect to "always" pay 5% to ebay when it sells.
The odds of a given promoted item selling without the 5% promoted rate is getting close to zero. (Having said this it probably wasn't that much above zero in the past, non promoted purchases of otherwise promoted items, at least in my own experience was very small)
My somewhat fragmented memories of the olden days here recollect something like this a long long time ago, one paid a fee, although I think it was a fixed fee to be "noticed". This is theroetically the same concept.
I could very well be wrong, but it looks to me like the algorithm apportions more emphasis to items that have views (and/or bids) than perhaps it did in the past. That would also explain the "reason" behind it, although I think the pay to play AI comment is likely more accurate - although as I mentioned this is far from the first time this happened in ebayland.
I've noticed in my categories, its saying 25-30% of the items in the category are promoted. This is a fairly significant number indeed. The good news could be that if enough frustrated people drop standard promotion, it will benefit those who persevere (both in terms of how much it costs to be more noticed and the likelihood the items sell). At least in my case, going from paying the promoted fee 10 times out of 10 isn't much worse than 9 times out of 10 (this is hypothetical), especially if it means I sell more.
The "crazy" high promoted rate of the last few years has meant that one of my mainstay type of items is no longer selling anywhere near where it once did. This is because there's a lot more comptetition out there and folks willing to pay significantly higher promoted rate than I am willing to. As a result I've "evolved" to put less emphasis on this type of selling and more on other types which is working out ok.
Just as with all changes to "getting noticed" over the last 26 years, one has to adapt as appropriate for one's own selling scenario - along with frustrations there might be opportunities too - time will tell!
