The final distribution medium and specifically where they prospectively will be played and with what ideally dictates the mix and master. It is not unusual to have the mix engineer do a dub and take that to his car and drive around just as an example. If people really want to know the real reason the loudness wars started, it started with portable radios, long before digital entered the market.
LPs will be played at home. The lower noise floor allows for more USABLE dynamic range. CDs are both portable and ubiquitous. The production team needs to factor in the worst case scenarios like as mentioned, car audio. We know what a hostile environment that is with all the road and engine noise. The LP producer doesn't have to worry about that. Now we have Mastered for iTunes which by spec should be better than CD preps because they are primarily geared to headphone users who are more protected against external noise especially when using IEMs or close backed headphones. Even with buds and open backs the level of external noise is less. Just not as good. No need to squash that mix as much either.
Now this is not to say things can't swing around the other way completely. I've come across some (now defunct) "audiophile" labels that churned out CDs that were so quiet on one end that you had to constantly ride the volume control and on the other end played with processing so much to make things sickeningly airy highlighting reverb and decay trails. In a word, gimmicky. Then there are the labels trying to cash in on the vinyl resurgence. No surprise the LPs sound awful compared to the CDs from which they were derived.
Many of us are drawn to the sound quality of recordings done from the 50's to 70's, even guys like me who were born after the golden age of recording. I believe the glue is that this was the period where most listening was done at home with free space stereos. It was the time where a lot of people just sat down and listened. Recordings of the period reflected the listening habits of the market.
I've said it many times before that Mastering is the icing on the cake. The whole cake starts with the musicians and ends with the audience. Now try to imagine the infinite number of choices that are made throughout the entire process from creation to production to reproduction to appreciation. It is simply mind boggling.
I collect music, I'll take it in the format that works for where and how I'm going to be playing it. The hardest part is getting the system to play equally well regardless of format. Physical set up will always skew towards the best possible performance of the most used and preferred format at some compromise to others. Human nature.