I can only speak from the instructional viewpoint: In the mid 80's, when the IBM P.C.was relatively new, I was ground instructing far from the U.K's shores. I had a colleague who had no flying experience but was involved with teaching our (military) students all about computers. We were not allowed to fly there, but he started to get interested so I lent him a copy of the old FS2 for the IBM P.C. He practiced assiduously every lunchtime and after about six months, when on leave I suggested he try the real thing. Within about five minutes of airborne experience in a C152 he was able to fly it like he had had about 3 or four hours of instruction. Then, in another fully equipped aircraft, he demonstrated that flying V.O.R.radials was no problem and we finished the detail by him flying an ILS down to 200 feet with no interference of any kind from me!
A few years later the I.M.C. syllabus was upgraded to include ILS and ADF approaches and increased to 15 hours training to cope. I always found that with 15 hours training students could only just get up to the standard required. However if, when they started, you suggested that they got a flight sim program for their computer, their standard in 15 hours training approached that of the I.R.
These days flight sim software is much more sophisticated thus I expect that when used for procedural training, even higher standards should be attainable. After all, how do those competitors on the Krypton Factor sometimes manage to fly B737's and so on so faultlessly?!