Well you are kind of screwed when you have lots of champions with bad/no engage
Though there is always flash/ghost/Horn to catch up to them
But yeah melee teams often win if the range team isn't able to kite and poke them
I'll admit there are some harder matchups. But for every ten melee versus ranged matchups, eight of them the melee champs are going to have some good engage/hard CC, because most melee champs who aren't assassins have engage/hard CC. And of those remaining few truely lopsided matchups, its often because someone in the lobby saw their team had low CC, and then decided to reroll the strongest CC champ on the team. Which is fine, you're allowed to reroll if you really want, but I often see 'good' champs rerolled in the hope of getting 'fun' champs, which tends to result in a loss.