I would not say that it's impossible for a roof to equal the performance of a quality porro. I would say that it appears to not be easy, based on what's available on the market.
When it comes to the 8x32 SEs in question, I've only compared mine against the 8x32 ELs, the 8X32 Ultravid HDs and the 8x32 FLs. In my experience, using the individuals samples I happened to buy, the 8x32 SEs were better than any of them. They were distinctly brighter than either of the first two (the Ultravids also crowded my glasses), and while the FLs were at least as bright they were not quite as sharp. The hand-feel of the SE is also much less fatiguing to me than the barrels of the smaller-format roofs.
Now, these are not quantifiable, scientific results, but they were the product of more than picking them up and looking around a store somewhere. I owned and used all of these bins. I hunted and birded with the FLs more or less exclusively for more than 6 months before I sent them on their way.
Other users might have come to different and equally valid conclusions on the same binoculars. The roofs are waterproof and have ergonomic advantages that other people might value more than I do. If CA sends you screaming out of the room you would likely prefer the FLs to the SEs. In my case, I had to go to a much larger bin to get noticeably better performance in a roof.