Why do people argue in favor of IQs, while then encouraging people (of any IQ) to use hard work to obtain the same successes?

At the same time people will say (science included) that IQ is a very important thing — while at the same time saying that people with lower IQs can do things that people with higher IQs can — while again coming back to IQ as some rigid qualification to employ any means or abilities in life to a degree.

If IQ is important, would that imply that one should not pursue certain areas/sciences/etc. if they have a lower IQ? If not, wouldn’t telling them that they should continue to learn and pursue what they wish just discredit the previous argument of IQ’s supposed weight/purpose? It seems contradictory.

For those who argue of IQ’s importance and (mostly) rigid nature, they are essentially standing for the point that IQ is not easily changeable — if at all — and that IQ has prominence in determination of one’s means somewhat. But so many who stand behind IQ will also stand behind the idea that one can use hard work and that IQ “doesn’t tell all” just right after discussing the correlation between IQ and people in sciences, math, or just in general/some specific areas/etc. How does this argument make sense?

The rigidity of the IQ argument and its connection to genes postulates that you can’t really “hard work” your way out of the disadvantage very much. So we could go on a limb and say this idea is very specious (the suggestion that people with lower than “ideal” IQs for ‘x’ or ‘y’ should just study harder).

I can’t — in any good faith at least — argue that IQ is powerful and meaningful and not very changeable while then arguing that people can use hard work or etc. and pursue the same interests just as successfully as those with higher IQs in the end. If I made that argument I would quickly see my illogic.

If someone says, “IQ determines success potential,” then follows with, “Hard work can make you successful anyways,” the resulting conclusion I gather is that:

1.IQ is not that important to success (and is then assumed to be not as powerful of a tool of human capability overall), and hard work — not strongly tied to IQ — can gain one success;

2.IQ is important. The reason people succeed with lower IQs as compared equally to people of higher IQs in the end is because their IQs must have provably increased; which means IQ is changeable too.

These two previous statements, or finally:

3.Some people use some other means to succeed that do not fall back to IQ’s potential/limitations/suggested means somehow, as compared to others’ performance with higher IQs.

I get that using the term “successful” may not have any perfect meaning — but within equal fields, measures and performances, correlation with IQ to ability/means seems to be how people validate it.

I do understand that in no one way anyone is suggesting that IQ is the be all, end all of human brain/human capability or capacity. I know one can argue that IQ has no provable correlation with stuff like: self-awareness; sentience; drive; strength; etc. My whole reason for asking this is to see where, logically and in any other such ways, people stand in defending the importance of IQ and its rigidity along with its role in brain power/human means, while also suggesting that people should continue to learn regardless of such a factor that was just previously stated to be very useful at seeing said means.