Why not? Shouldn't a Universe comprised of 90% dark matter allow us to assume that our galaxy would be similarly endowed.
Why can't we observe the bending of light resulting from gravitational force's of dark matter routinely?
Have their been any signifcant studies of by astrophysicists trying to observe same?
Not directly inferred, no, but observations of the velocities of the stars and clouds of Hydrogen that orbit the galactic center indicate that the mass distribution of matter in the galaxy is not all accounted for by the clouds of gas and stars that are observed, hence inference of dark matter.
Have their been any signifcant studies of by astrophysicists trying to observe same?
Yes. There were the hunt for MACHOs (acronym for MAssively Compact Halo Objects) that as far as I know are still occurring. These are programs in the Southern Hemisphere that look at stars in the Magellanic Clouds nightly, and look for gravitational lensing events. They use star fields that are extremely dense, to maximise the number of possible lensing events in each frame. There are also some programs that look toward the galactic bulge.
Check out:
There are probably more projects, just do a web search. These are just what I'm aware of. They have had some success, but not at the amount necessary to claim their detections are actually dark matter.
I don't know who you are quoting, but these are not my words. However, I'll answer your questions.
Yes. Evidence of such exists. See the NASA web page.
This has been observed.
Yes. You may wish to consult the literature.