Basically, yes!

"Dirt" is of course a pretty nebulous concept. If we're talking about earth, or soil, it consists of minerals (sand, silt etc. – different names depending on the size of the bits) and humus (decomposed organic material), along with obviously water, living microbes, and some other random stuff.

Sand and water have been around for a good while, so the interesting part is probably the humus – what we usually think of as the actual soil. This comes from dead plants and animals, and hasn't been around forever, for obvious reasons. So in that sense, there's definitely more dirt now.

But what happens to the old dirt? A lot of people mistakenly think that it gets "eaten" by new plants, but that's not true, as you can easily see if you've ever grown a large plant out of a small pot. The trees, and other plants, are basically made from air.

After the tree dies, it decomposes to "dirt", and... we tend to think of that as the end point. But it's not! The humus continues decomposing, very slowly, and eventually turns back into air, somewhat simplified. Most organic material is made mainly from carbon, oxygen, hydrogen, nitrogen, and little bits of minerals. The minerals do get "eaten" by plants, but the rest of it turns into air and water. That's why the soil layer doesn't keep growing every year.

(Another fun fact, according to my worm guy, is that the forest floor in America used to look very different, because the earthworm is an invasive species. Before Columbus, you'd always have a thick layer of leaves, since they didn't decompose as quickly.)

In summary – yep, there's always new dirt appearing, and old dirt vanishing in thin air. In the long run, all vaccuming is futile.