Russian equipment is not junk, neither are they unreliable though the west would have us believe so. Russian equipment is cheaper and economical. They may be comparatively low tech but the ILs and the ANs and the MIs are used the world over. There is absolutely nothing wrong with the IL-76/78s that we use. These along with the AN-32/12s have been the work horse of the IAF for many decades. It is only since the disintegration of the Soviet Union that the problems of spares and servicing have cropped up. We have been very patient with the Russians and have waited for them to resolve the issue. They have made progress, but issues till remain. Ultimately, we have to look after our own interests too. The IAF is therefore correct in exploring alternate supply chains for spares and servicing.
The C-130Js and the C-17s are not meant to be a replacement for the IL-76s. The C-130Js are for the Special Forces. This will release the IL-76 presently doing that job and make them available for other transport/cargo duties. They can also be used for moving cargo to distant unpaved, grassy landing strips the size of football fields. The C-17s are strategic heavy lifters. If you wish to transport MBTs and APC to distant parts, these are the birds that will do it.
As some members here have correctly suggested, India needs a mix of rugged and economical Russian equipment along with expensive, high tech and top of the line American/European equipment. The additional benefits of Russian equipment is that they come with no strings attached. That is not always the case with American stuff.