The older car sound enthusiasts like me and others in this forum don't want the loud SPL systems like before and a lot of the major brands are geared toward SPL. We want a combination of SPL and SQ with more SQ than anything else and feel like unless you have $2000-$3000 to spend on a lot of the top brands then older amps will give you that combination. There are very few brands made today with the made in USA quality that give a blend of SPL and SQ.
Old School is a term where we think times and things are better than what they really were. To me 1988-1999 is old school. To others 1979-1985 is old school. In 20 years, the 20+ year olds on this forum will think Sundown, Atomic, DD, Audioque is old school. One thing for sure though is that the trend of making amps in Korea, China and Taiwan has ruined amps and car audio because now it's all about quantity more so than quality.