On a known clean engine and if you can dissect a filter I see no reason why you can go 10000 miles on a filter. I'm running 10000 miles on my Harley using amsoil filters.
My Harley is highly modified. Cams,heads,dynotune.big bore kit,bigger tb etc. I'm currently using rotella conventional 15w-40 at 3000 mile intervals. I couldn't be happier with the oil and the price is tough to beat.
In my shared sump bikes the shift quality gets notchy and tight around 3000 miles on the oil so as soon as I notice the shifting is getting tight I change the oil.
In the shared sump bikes I've used everything from m1 v-twin and the 10w-40 4t oil,motorex 10w-60,amsoil v-twin in all 3 flavours,and motul 4t and 20w-50 as well as motul 10w-60/20w-60(I forget which)
Of all the synthetics I've used in the shared sump bikes I can say truthfully that only the motul retained shift quality up to 3000 miles. None of the rest lasted as long as motul,and rotella.
So in my experience rotella is the best oil for the price of all of them in regards to sheer resistance. That is an important feature when used in a shared sump bike.
It surprises me that sopus doesn't market it as a bike oil.
As has been proven with their nonsense in marketing ultra they aren't quite on the ball in that respect.
Anyway since switching all my bikes to rotella even though I've shortened the interval by half it still costs me less in maintenance then when using high priced synthetic.
Synthetics do have their merits,longer intervals being the primary one,easier pumping when cold but neither of those merits really matter in a bike since most of us aren't running short intervals or running in the winter.