What you've read is false. You may not end up with a bodybuilder's body, but push ups is a fundamental exercise everybody does, whether going to a gym or not.
It definitely helps you gain muscle mass as long as you keep challenging yourself and altering your workout to target different areas of your chest as well as to prevent your body from adapting to the routine.
You can find some great push ups variations here.
TIP: A nicely shaped, muscular chest is considered the one that is full and symmetrical, so be sure to target a lot the upper chest with decline push ups. Regular push ups don't target it as effectively, since the targeting angle is different.
Warning: Your routine has to be fundamentally changed in order to see yourself gain muscle mass. Currently, by doing 140 push ups everyday (I counted 240 from the sets you provided) all you achieve is to overtrain your mid-chest section consecutively without allowing your body to repair your muscle tissue.
Advice: What you should be doing instead, is follow a gym-like routine and train as if you were actually going to gym. That means that you should be training 2 days per week with at least a 48-hour rest period in-between to allow proper muscle tissue repair and recovery. You should also, use 3-4 different variations of push ups in order to target all different angles and thus train all the muscles of your chest.
- Standard push ups: 4 sets x 10-15 reps, 60 sec rest between sets, last one to failure
- Decline push ups: 4 sets x 10-15 reps, 60 sec rest between sets, last one to failure
- Elevated push ups: 4 sets x 10-15 reps, 60 sec rest between sets, last one to failure
- Optional (if you can still move your chest after the first three)
Before anything else, read this article on overtraining and refrain from the kind of routine you have in the future to avoid both the physical and psychological ramifications that will otherwise occur.
**Failure means until you can no longer complete another repetition.