Some American restaurants, indeed, do use tablecloths and placemats. Below is a picture of Charlie Palmer’s restaurant in DC, as an example (and, of course, for attention to the answer).
I think that what you’re asking is “why do many restaurants tend not to use tablecloths or placemats?”.
More On Placemats
Cost– Mathematically, spending $2 or $3 per laundered tablecloth is a lot compared to the $0 cost of having a server or busser wipe down the table with an old rag.
Many dining establishments have cloth linens, and most of them use an outside vendor for this service. Predominantly these are expensive places, well worth the money but pricey.
There are high-end places that won’t have linens, most steakhouses and BBQ’s traditionally eschewed linens as a more “cultural” reasoning.
Frankly, I often am grossed out as well when I see someone wiping off tables, particularly with a cloth dipped into a bucket full of dirty water.
I think that what you’re asking is “why do many restaurants tend not to use tablecloths or placemats?”.
