Why is there no set with much RC Straight tracks? after visiting many Lego events (brickmania, antwerpen, BE), I wish to expend my train layout much more than adding a box or two of 7499 ...

Why does Lego didn't released a set with, for example 24 straight track ( #53401 )

Even if 7499 contains flex rails, I don't like these, they are noisy.

Any tips for finding some ??

I can't imagine peoples who exposes layout in 5 meters by 8 meters with 4 tracks have bought a palet of 7499 !
According to Brickset there are 8-8 straight track pieces in both of these sets:


7896
7499


This seems to be the maximum amount, even the large complete train sets do not contain more than 8 straight tracks.

You might have more luck purchasing them piece by piece from other AFOLs, or see if there is a Pick-a-brick shop in your area.