Helicopter, there's only one word I would change in your fourth-grade report, and that's "good", from "the sound is not as good."
One of the problems is defining "good". This thread has pointed out that the surface noise on vinyl records comes in two types. One of them is the "vinyl roar", or scraping noise, which tends to low frequencies in my experience (and based on the FFT's I've looked at from silent grooves--none of which I have handy in my present location). Record a silent groove to your computer, using a level that brings peak music to close to 0 dB, and then analyze it in Audacity to create a spectrogram using a fast Fourier transform (FFT). That will show quite a high noise level in the low bass region--maybe as high as -40 to -35 dB. Dust, micro-scratches, and transients caused by large scratches create a lot of transient noise with wave shapes that demonstrate the high-frequency capability of the playback system. (I'm not even including damaged high-frequency response from LPs that have been overplayed or played using a worn stylus or too much tracking force, or the tendency of many cartridges to hot-rod the high-frequency response.)
Both of those noise sources are objectionable or not based on a range of issues. One is the playback system. Many playback systems mortals could afford back when LPs were the standard delivery medium rolled off in the top octave. For example, my Advent loudspeakers, which were
extremely popular in the 70's, roll off above 14 or 15 KHz. The "New" Advent loudspeakers, which I used, extended those a bit, but they still rolled off. That doesn't affect musical information very much, but it does affect some of the room acoustics in the space where the music was recorded. It also affects some of the intentional distortion products from amplified musical instruments used in rock music. Most of the time that roll-off has no real effect on the listener experience, particularly for we old guys who still fiddle with turntables. It clearly minimizes some of the effect of that high-frequency surface noise.
And speakers like those Advents, which used an acoustic suspension design that dominated the product space in the 70's, at least for classical music listeners, demonstrate a very tight and controlled bass, sometimes to a fault. That helps keep that vinyl roar from resonating and booming.
So, "good" systems of the vinyl era lacked the ability to emphasize the noise products inherent in vinyl playback. When played on systems that are truly linear to frequencies in the 20's, or in the top half of the top octave, we hear that noise more clearly (unless our old-age hearing is already rolling it off in the top octave, which mine certainly is). A system that makes vinyl sound really good, by minimizing the frequencies where those noise products are most objectionable, might close up a cleaner, more linear source technology such as CD's and digital playback.
Vinyl can sound really nice in a system that makes best use of what it's good at and helps mask what it does poorly, but in no way is it as transparent as digital playback (that's what you mean by not sounding as "good", but it assumes that transparency was the objective, at least in those days). The coloration that is the reason for a lack of transparency, because that's what we were used to, was our reference. CD's at first sounded brittle and crispy, especially if our system sounded brittle and crispy for those added frequencies (and without the masking of that floor of vinyl roar in the low bass). The psychoacoustic part includes the contribution of our expectations, and if we expect what vinyl does, the violation of those expectations will be a distraction initially.
But, yes, alcohol helps. So do Advents, in the absence of old age.
Rick "afraid of words like 'good' and 'bad' that have moral and judgmental overtones often aimed at children, as opposed to 'transparent' and 'colored', or even 'appropriate' and 'inappropriate'" Denney