Albeit some Atmos engineers are better than others.
Atmos mixes are not “just thrown together” and now, more often than not, the Atmos mix is primary and the stero mix is simply folded down from the Atmos master.
Generally speaking the artist is not "creating the mix" - they are giving input, and approving it, but not creating it. A mix is made after recording, by a mix engineer. The job of the mix engineer is to place all the stems within the stereo (or in Atmos, XYZ) soundscape to make them all work together, including adding texture, effects and balancing all the elements to make them sound right.
An artist will say what they want, they (or their label) will be involved in selecting the mix and/or mastering engineer, and someone will approve the final mix.
The example of Beach Boys and Beatles mixes being "thrown together in an afternoon" mix have been true 50+ years ago, when stereo was the new cool thing, but that was 50 years ago...
However, the idea that an Atmos mix is "corrupting the mix created by artists" is just not the case - for the reasons above, but also because most frontline music is being mixed in Atmos by default now: that's because of various things including future proofing, but primarily because some streaming services (Apple Music in particular) offer an uplifted royalty rate for "spatial available" audio.
You can read more about that here:
https://itunespartner.apple.com/music/support/5216-deliverin...
"Creating music in Spatial Audio takes a high caliber of dedication, and Apple Music acknowledges these efforts. Spatial Audio content receives a greater share of sound-recording royalties on Apple Music than content not available in Spatial Audio, by a rate of up to 10%."
So pretty much anything current via a major label (Universal Music, Sony Music, Warner Music) is going to be delivered in Atmos. The major labels are also remastering high-performing catalogue to take advantage of the royalty uplift.
Whether an artist is directly involved in approving a mix or not depends on a whole bunch of things - but someone is definitely approving the mix, and more importantly, someone is selecting and hiring a mix engineer who understands Atmos.
You can read Universal Music's guidelines on Atmos mixing standards here:
https://contentguide.universalmusic.com/dolby-atmos-audio-be...
In particular, it's worth noting statements such as "This section aims to support you in your workflows based on our learnings from the past years of working with Engineers during the Dolby Atmos mix and Mastering process."
and
"UMG will review Dolby Atmos mixes to ensure a quality experience with meaningful format engagement."
Apple has some pretty specific guidelines about what is allowed when delivering content as Atmos - from the document I linked to earlier.
In particular "Upmixing from a stereo release is not allowed. Extracting stems (“de-mixing”) from a stereo release is not allowed. A Dolby Atmos track consisting only of a stereo mix placed in the sound field with added ambience or reverb is not allowed."
You may be hesitant to take me at my word, but I can assure you I have detailed knowledge of this area. I think I've found your instagram profile (which is similar to your username but with an additional word) so I'll message you proof of my credentials if you wish.