My team rarely has a tank? Don't people look at team comp?

So recently I have noticed that the enemy team usually has 1-2 tanks on it when I lose and my team will generally have 1-0. I definitely understand I myself could play more tanks and am currently working at getting better at that role. It seems pretty consistent that when I lose it starts in champion select. I could be first pick and go lux support and my team will think its cute to go AP top nidalee, ryze mid and a fiddlesticks jungle. That's a horrible team comp. Who in their right mind thinks that's smart? We needed like a nasus top, (inserts a better mid then ryze at the moment), and then a fiddle jungle might have been viable.

The last game I played i lost terribly because we had a poppy top going pure attack speed (not tanky at all), a shaco jungle and a lulu bot (who never casted polymorph or glitter lance the whole game), and I was MF (last pick). I was winning my lane for the first ten minutes until i got stomped by 4 champs at once bot. If i were in B5 I would expect this trashy play. How come people don't understand that team comp makes or breaks a game. You need a tank, good CC, a fast attacker (hopefully your adc), a busrty APC, there are many champs thats meet multiple requirements, however the players i seem to play with don't really understand that.

In short whats a summoner to do in solo Q?