Have you ever played with a team?
Unfortunately its not always as simple as just learning off smokes and calling smokes A Mirage. There needs to be coordination, there needs to be second precise timing. Flashes even more so because of the coordination and trust involved to flash perfectly for your team every time.
No there are not 47447733774 permutations but you have to appreciate that there are a lot of individual scenarios that need to be considered depending on you economy, the other teams economy, advantages or disadvantages; whether its 5v5, 4v5, 5v4, any read or information gained during the round.
So yes many of the pros will know most of the smokes/flashes, but the other teams will also have counters for these known smokes and flashes and will likely have a team approach to counteract them, so to play at that level it will never be that easy.