Not exactly.
But there is a common sense rule that you should never expect to have PA support in this genre. Ever. So if you want your loudest parts to be bonejarringly loud, in this genre, you need to bring the firepower to do that yourself.
Though, honestly, it doesn't always take much. I mean, I play through a very large 2x15, but it is still only one 2x15.
A lot of the people with huge cab rigs, I'm guessing, have so many drivers partly so they don't have to worry about blowing them up with low end.
SubRosa managed to do it just fine when I saw them in Oakland. The guitarist's rig for that night consisted of two old Sunn Model T full stacks, turned up loud enough that she seemed to be mainly using the guitar's volume knob to switch from clean to overdriven.
Their vocal harmonies came out fine.
However, here, there is something you actually might be missing. It is actually very easy to hear your voice if you are wearing ear plugs, which most doom bands do when they play. I have actually had a much easier time staying on pitch in metal bands where I was wearing ear plugs than in my folk/rock band, which I generally don't wear ear plugs in.