If I understand correctly, they say this is only the case when you have less than 1000 flies:
@pika/web's installation most closely matches the study's moderate, "50 file" bundling strategy. Jung's post found that for HTTP/2, "differences among concatenation levels below 1000 [small files] (50, 6 or 1) were negligible."
Our app is certainly over that, and I suspect most apps quickly grow to this (most of the files
are dependencies). I'm not sure where the 50 moderate number comes from (we have an unfortunate dearth of information when it comes to "real world test cases" -- it seems common for bundlers to just check whether it performs better for the app they were working on at the time), but I would be surprised if most the 50 file threshold is maintained for very long for highly dynamic sites (vs., say, a company brand site or a blog where this may be the case forever? Again, I honestly have no idea).