Ps3 not recognizing only the game BDs

Hi,
I own a PS3 slim 320gb which I bought about 3 years back. It was working well till August'13. Suddenly, it stopped recognizing the games disc for no good reason (my internet was also down, hence could not update the software). However, I tried every thing in my power to fix this issue. First, I tried inserting a dvd and the ps3 accepted it & I was able to watch the video clips. Second, I tried inserting different games, it took forever to recognize game. Even now I face the same issue. If I have to make a game bd work Id have insert the bd, take it out and insert the bd again.. and repeat the process for about 20 minutes before my ps3 could start reading the disc.
I certainly concur that there is an issue with the ps3; however, I fail to understand this peculiar issue. If the lens is faulty then the ps3 should not be able to read the bluray discs no matter how many time I take it out and put it back in but to the contrary, it starts working after 20 minutes or so. Ever since this issue was thrown at me, I have been downloading games directly to my harddisc. If I hit restore to factory settings then I would have to download close to 200gb worth of games all over again.
I even tried opening the ps3 and cleaning the bd lens with cleaning alcohol, even after that I am facing the same problem. Every time I put a disc in the ps3, it makes a weird clicking noise for about 10 seconds and it makes a noise like it is ejecting the disc (same noise as the ancient vcr player used to make whilst ejecting a cassette).
Is there any solution for this problem or should I give the damn thing for servicing or just chuck it and buy a new ps3 considering the fact that there is no backward integration in PS4.

Thanks,
Sandeep