It’s not all hand work though. Power sanders and finishing sanders exist. We poo-pooed random orbital sanders in the 90s but modern ones are much better.
You can fine tune the dimensions of material almost like one would with a belt sander, as well as use them to finish a surface.
Even with power tools, sanding a large piece (eg, a bookshelf or a desk) can be a long, slow and dusty process.
(The first time I did a large project I just hit it quickly with some 120 grit sandpaper, and it was fine but as time goes on I spend more and more time using more and more grits of sandpaper, and that delicious smooth you get is almost addictive.)
