can you feel my heart?
I suppose, wouldn't specced Stamie be able to deal with it though? Or do most standard sets have thunderbolt on them? -_- Sorry I'm still new and still don't know the most common sets used haha.
They have the same base speed, meaning it comes down to a speed tie. No, but they run Shadow Ball which gets STAB and is super-effective on Starmie anyway. The thing is, with a Sub Gengar, they have the ability to lose that speed tie and only have their sub broken while they OHKO your Starmie with Shadow Ball. And if they win that speed tie, they OHKO you and keep their sub. The substitute is like a wall of protection; it lets them predict easier and makes it hard for you to kill it - once you use say Jolteon to break the sub, it'll have the chance to attack and presumably KO your Jolteon. Basically, Substitute lets Gengar beat things that outspeed it so it can sweep later on, and Conkeldurr/Lucario have the distinct disadvantage of giving it a free sub, basically.
This is a problem that everyone that runs Conkeldurr/Lucario has, and it's not too huge of one as long as you can prevent Gengar from Disabling your Payback/Crunch on the turn you use it (ie switching out on the predicted Disable). It's just that a Gengar with the ability to take a hit (ie one behind a Substitute) is much much much more dangerous than one without (ie one without a Substitute).