How long will Sequoia with Mobile 1 synthetic last?

I am not 100% sure if it is my imagination or it is true.

Every time after change oil, I had about 2K to 2.5K of enjoyment and then I
started feeling the engine is louder and not as silky.
I heard that Mobile 1 synthetic can last easily 5K for oil change interval
but I don't feel smooth throughout the 5K at all.
Am I mistakenly lengthen the oil change or...?

If it never last 3K of good time, I might as well use dino oil and change it
every 3K. I have been changing oil every 5K in last 25K, should I change
the interval?
What is your observation and suggestion?

BTW,
I used to drive this car 90% highway, 10% local and now 80% local.
It seems the lasting on oil quality not quite related. In both cases, I
started feeling the loss of silkness after 2K...