I wouldn't be surprised if most of what you do is getting the volumes more consistent between different albums with some subtle EQ'ing here and there.
Sure, a lot of that happens with 35-50% of the audio. Nothing more than a simple gain adjustment and subtle EQ. Keep in mind, my collection of audio starts at 1937 and half of it was made before 2000. I continue to buy new music in 2018. The music since 2005 is less likely to need significant adjustments.
However, a lot of the pre 1995 content and even some 2005+ content really needed some major remastering to hang with my entire collection played randomly at an average 16-12rms. This included broadband compression, frequency specific compression, stereo width adjustments, complicated EQ, transparent limiting and occasionally a touch of reverb. Some really old recordings benefited from some noise reduction.
Robert Rich and Steve Roach have been making excellent music since 1980 something. However, there is a very big difference in the way they master their music today. I prefer the way they master their music today.