The Supremes aren't my favorite Motown act - a bit too thoroughly cleansed for white tastes for me -, but there is no denying that they were a blueprint for black female vocal groups like Cream and the Jimi Hendrix Experience were a blueprint for rock bands: No Supremes, no Destiny's Child; no Cream, no Metallica. It's that basic.
Without Motown and what it stands for, black music wouldn't be what it is today. The Blues was at one point almost wholly ... culturally appropriated (is the term you would use today) by whites and they turned it into Rock'n'Roll and then Rock with its million subgenres. But black (do I have to capitalize it?) people retained artistic control of Gospel, Soul and Funk and it spawned Motown, Stax, Reggae, Phillysound, Disco and what is today called RnB plus - urbanized - Hip Hop and Rap. Motown is not just music, not just a record label, it's a cultural and social phenomenon of Black America (I think it deserves capitalization here).
"The goal was to get hits by any means possible, never mind the quality of the music." Yes, of course - and your point being? It was black people wishing to entertain, make money and leave a cultural imprint in an era when the single and radio reigned supreme (no pun intended) in the media world.