where (x, y, z) in ((x1, y1, z1), (x1, y1, z1), (x1, y1, z1), (x2, y2, z2)) (not) optimized

Hey folks,

I have question really for all mighty developers, but don't want to
spam -hackers with it.

why :
select * from foo where X in (1,1,1,1,1,1,1,1) --- same values in search.
or select * from foo where (x,y) in ((1,2),(1,2),(1,2),(1,2),(1,2),(1,2),(1,2));

never gets optimized by planner, etc ?

Is it just not worth optimizing from pg side? I am sure, it would make
sense to actually reorder these values, so that index/whatnot could
pick it up faster.

Just another one of those, 'why' (not) questions from my side.

thanks.

--
GJ