If we don't chew, our jaws would not develop. The bone growth of our faces would change and our teeth would become incredibly crowded and crooked.

One of the current leading theories for why we now often need braces is called the Soft Foods Theory. The basic idea is that we eat much softer foods than our hunter-gatherer ancestors did, so we aren’t stimulating as much bone growth in our jaws when we chew our food, which leaves our teeth with insufficient space to grow in straight.

If we didn't chew at all and just took pills for food, we'd probably need to get all of our teeth removed as part of growing up, we'd have no chins and we'd all talk much differently than we do now.

I like the Fifth Element's take on "pills for food."

Put pill on plate, put in a microwave type thing for 2 seconds, pull out an entire roast chicken with fixings.

Mmm... Chikahn! 🤤

Well our mouths wouldn't change just because they are no longer needed the way they were before.
It would only change if there was a negative effect of having a mouth and teeth like we have now.

You could say if we don't need our teeth anymore, they might disappear over time, but that would only occur if having teeth lead to higher death rates and fewer children being born. But we've generally come so far with our technology that we're not really that much dependend on the "survival of the fittest" rule anymore.

If we didn't need our teeth and let those people who have tooth decay die from infections instead of treating them with our modern technology, then very very slowly those who had a random mutation that leads to them not having teeth at all actually have a better survivability than those who have teeth. But as we treat them, they have the same chance of reproducing as everyone else.

You could also argue that it's better for survivability to have as few body parts on you as possible that you need to provide energy for and those parts that you have being most energy efficient. So it could be that we at least develop smaller mouths when it's no longer a benefit of having a bigger jaw etc. But this also wouldn't happen because there is no reason why someone would die of having to spend too much energy on their body nowadays.

Humans have decoupled themselves from evolution in the typical sense.

Survival/gene-elimination cues don't really apply anymore since we have hospitals and can take car of eachother.

I think the major remaining factor for our evolution now will either be self guided, or it will be who ever can have sex the most.

Semi related: I recently lost my taste for covid reasons and during that time I'd happily eat those pills if I had no taste.

Since mankind mostly decoupled from natural evolution, we wouldn't develop other mouths. But our look would still change because the jaw muscles wouldn't be trained and maybe our facial expression could become very underdeveloped.

It could be a possibility.

That might also mean that companies could look to create things that worked out our teeth and jaws to prevent that from happening (or maybe slow it down).