It seems like I broke the system. I could play longer, but my hand was tired. Probably would be much better on the phone. I've tried playing on mine, but dragging was not working there.
I think you should speed up the lanes with each wave. Then it should end up at some point. I would also add some bonus for matching colours or some penalty for using non-matching colours X times in a row (if there was proper colour match available). Right now I think it's not enough. Of course it's better to remove 5 with one card instead of three. But selecting right colour sometimes takes so much time that it's faster to throw three random cards.