While hopefully it's fairly likely that the profiles which are being constructed based on our online habits won't negatively affect our day to day life, there's a chance that they will and that risk is worth managing.
One scenario to look at is the past behaviour of other big companies during war time or during periods of authoritarian regime when the incentives align between the govt and private entities. There are too many examples from WW2, but also look at how willing many companies were to get their hands on (and share) information regarding figures in the various labour movements throughout English (and American) history, even the ones which weren't explicitly communist. Another example is the big (european car?) manufacturers' cooperation with the regime in Argentina in the '70s who weren't really hiding the fact that they were disappearing the people who these companies were doxxing for identifying with certain social / political movements.
It's just worth keeping in mind that anything you do now which might identify you with a certain group could come back to haunt you if that group becomes the new Reds Under The Bed in 1, 2 or 5 election cycles. And that at this stage you are doing what you are doing with the full knowledge that everything is being retained for use at the discretion of these tech companies.
So I disagree with the idea that it only matters of you ever 'make it'. It also matters if you have shown patterns of behaviour which suggest that you identify with a group that makes it.
That said, I definitely don't do enough either. I only really take the simple steps that others have outlined here.