RE: why do supplements take so long
That's a bit like saying the sky is blue - no actual point. If you meant to infer that supplements come and supplements go then yes I agree. Cissus (I have no idea about this at all) may prove to be a valuable long term sound supplement (like whey and creatine) but will almost certainly not be.
My knowledge and experience of the sport means I've seen a lot of voguish products, Mumie for example and god help me tried a bunch as well. One problem which happens is that some guys get an amazing response from a product and others nowt whatsoever. There have been a bunch of posts on Gakic extending the amount of reps trainees can do (endurance) but not of allowing them to be 10.5% stronger (lift more weight / strength) as per the claims. So it seems to work but not dramatically so. Similarly NO products give some a great pump and others sweet fanny adams (me). Voguish supplements like those mentioned will come and go. Esterizing products is a fave of the moment regardless of whether or not all supplements can benefit form being so treated, or that that is the optimal form for them to be taken in.
For years casinates where all that was available to the average Joe and then whey made a name for itself. The price dropped to the point where, if you were based in the USA and brought tonnes at a time, you could pay $2.00 a kilo. Then we started seeing Caesins being mentioned again and later on Micellar Caesin. In some cases it was not necessarily better just different and therefore attractive, 'leading edge' and sellable. As the customer became more educated and more and more info was available on the net we saw products very quickly tested in the real world and so products will come and go much quicker than before. The list of those worthwhile and which have stood the test of time is still quite short.
There is very little research done in any meaningful way by supplement companies that will speed up the bringing to market of products. They simply, no matter how succesful, do not have the cash. Muscletech claim to have set aside the most and it's still a small amount compared to a pharmaceutical company giant.