Lots of things wrong with this.

1) $1k is nothing in the world of hi-fi. Unfortunately, loudspeakers are one product where price absolutely does matter. Why? Well designed drivers tend to be expensive and have heavy magnets (or even more expensive rare-earth magnets). Acoustically non-harmful cabinets are expensive to produce and heavy to ship. The speakers they're comparing them to are not hi-fi. They're cheap home theater speakers.

2) Flat frequency response is a small part of perceived sound quality. Thought experiment: Buy $10 computer speakers and EQ them flat with a software EQ. Do they magically sound good? Of course not. Distortion, off-axis response, room interaction -- these are just as important.

3) "Audiophile" quality usually means a strong / stable phantom image. Most people haven't heard this before since true hi-fi system are rare. A properly designed system in a properly set up a room, with a properly recorded album -- the illusion that the band is in the room with you is very strong. This isn't even possible with a mono speaker.

4) Small speakers do not produce a meaningful amount of bass at normal listening levels. No amount of DSP can cheat physics. Without the lowest 1-2 octaves, you do not have high fidelity.

I have a small Sony bluetooth speaker on my desk. It's acoustically somewhat similar to the HomePod in the sense that it has high frequency drivers crossed over to a (inadequate) bass driver at a relatively low frequency. This type of design can have a pronounced clarity in the vocal range, which can be nice for some recordings.

Sony EQ'd the shit out of them and boosted the bass in the 100hz region (or more accurately and to their credit, shelved everything else). They don't sound bad. But you can't beat physics. The bass driver is too small. The stereo pair are too close together to create a phantom image. Their max output is very limited.

The HomePod isn't any different. Yes, it can EQ itself flat. But for where? The listening position? It can't EQ any more bass than that small driver is capable of producing -- which is probably not much below 60-70hz at normal listening levels. Room modes dominate in-room frequency response below 100hz. EQ can't fix room modes. More drivers at different positions can. Two (as in a stereo pair) would be a bit better. Two or three dedicated subwoofers at random locations would be best (yes, it's that hard to get right).

EQ also can't fix room contribution above ~1khz if that contribution is dominated by reflections. Omnidirectional speakers like the HomePod are actually the worst in this regard. (Directional speakers are the best, but that's a big topic). These reflections mask the recorded reflections / timings that allows your brain to construct a phantom -- the band is here -- image.

That's not to say they sound terrible. Omnidirectional speakers can sound "spacious" because of all of those reflections. A lot of drivers can mean more output / less distortion. But then you're anchored by your tiny bass driver. Good? Maybe. High fidelity? No.

The cynic in me says this is guerrilla marketing by Apple. Doesn't really matter. The product is a good example of what's "killing" Apple -- optimizing for a set of largely arbitrary metrics to fit the marketing style they seem incapable of moving beyond.

I put "killing" in quotes because obviously they're doing well. They are losing core supporters though, myself included. My new top of the line Macbook Pro has me swearing at least once a day (usually the window server crashing when I connect external monitors). And that touch bar, FFS...