I think it’s a definitional thing: “a great filter” assumes that life is basically everywhere and yet one specific something (or perhaps as many as “a few”) almost always prevents it from taking over a significant fraction of its future light cone.
If there are 10^30 stars in ours, the lower bound on the odds of surpassing it have to be close to that.
Personally I expect there to be many smaller filters rather than a few great filters — 30 things each with a factor of 10 has the same effect, after all.
Personally, abiogenesis by itself looks like something on the 10^-60 to 10^-140 range, so it fully explains everything.
Anyway, there are indeed a few things in our past that look like a 10^-10 odds filter, like each time our genetic encoding changed to increase our codons and the oxygen catastrophe. There are more that look like merely "almost impossible to survive" (I'd guess some ~10^-4 filter) like large asteroid impacts, but not nearly enough to make a difference.
If there are 10^30 stars in ours, the lower bound on the odds of surpassing it have to be close to that.
Personally I expect there to be many smaller filters rather than a few great filters — 30 things each with a factor of 10 has the same effect, after all.