No, some people are so stupid that they will never be able to do tasks much more complicated than e.g. sweeping the floor. You are trying to conjure a vision of the world that is comfortable to believe, but that vision does not reflect reality.
To me, 'everyone' does not mean literally every person but rather the vast majority. Whether this number is 95% or 90% is going to be interpreted differently. I think nearly all of us can agree that as intelligence falls on a bell curve there will always be those unfortunate enough to not be able to do certain tasks. However the nature of the bell curve does mean that around 90% of people are above ~80 IQ.
I see intelligence mostly as your rate of learning. That means you're competing with people who will get better faster than you. The only way to beat that is to outwork them, but there are only so many hours in the day.