How many people actually clean their filters? And of those that do, ho many would notice? I think the answer to both questions is not many..hmmm, 18+ years of production with relatively minor changes, and people keep on buying them. If it was that bad I'm have expected a few more people on AS to be complaining bitterly... and if it was affecting reliability and costing Stihl warranty claims, they have done something about it.
If you think the 260's filter design is great you must wear Stihl underwear.