Now, as soon as I'm reaching for packages outside of core, things change. But, again, as soon as I do that in any other package, heaven help me. We still haven't made our tables on our tools site align the numbers on the decimal point.
And if you ask TeX people how to do these things, they will tell you you don’t need to, at which point you will die a little inside.
I should add that I disagree that TeX has a good solution for decimal-point aligned columns. It has an absurd solution which involves dividing the column into two “columns”. As with many TeX features, as soon as you want to do this programmatically, it becomes a nightmare.(I don’t claim that any other markup languages are better at this – HTML still sucks for it - though Excel may do okay.)
Agreed that the TeX solution is bad if you want semantic markup of a table. If you abandon the idea of selective fields, it doesn't seem that bad to me.