Why must there always be one?
Ok, the whole point of any game with RNG every is favour. What do I mean?
XCOM, for example:
Is the height in my favour?
Is the cover in my favour?
Is the gun in my favour?
Do I have attachments that give my favour?
Do my soldiers give better favour than the rookies?
You can replace favour with odds, points, help or whatever. The whole point of a RNG game is to through everything you can into your favour, to unbalance it into your favour. It's literally game goal 1.
FTL:
I need to destroy these mantis ships, and I have a teleporter. I'll turn these melee's into my favour by buying a mantis.
I need a teleporter. I'll make it more likely that I get one by going to all of the shops.
I need some fuel, I'll make the choice to take fuel instead of fighting.
And so on. Yes, the RNG can sometimes bugger you over, but that's because you didn't balance it enough. It's just like missing a shot in a shooter, or not realising the enemy strength in a RTS. You are never perfect, so although you got that super-aim, super-stable gun, you may still miss. Even though you scanned the enemy base, they still had invisible soldiers hidden in the ground. The only reason you can't control the people in XCOM, or even FTL (Although you actually have a lot more skill involved in FTL) is because of the way the game is played. You don't go to play XCOM by switching soldiers and moving along. That game is called Ghost Recon. Also, that game is brillant and I love it.
Besides, there is a lot of skill involved that is not decided by RNG. Tell me, did you get angry at any point because the enemy quickly regen'd shields just as you hit, and this kept happening? Well then, disable your secondary gun and rearm it 1 second later than the other gun. Your timing means as their shields get hit, the second shot goes through and all of a sudden you are doing damage. The RNG has nothing to do with that. In XCOM, you could activate certain fighter abilities that guarantee hits and grenades that guarantee damage and cover destruction. I mean, hell even D&D has things that are skill based, rather than rolled. "I jump on the table and stab him from above, negating his shield." That is skill in a game that is literally based on dice.
If you cry about a RNG, unless the game is literally just click dice and if you get this much, you win, then you need to have a better look at what you are doing.