...but as everybody has EQ at their command, it's extremely rare to find any microphone that is unusable.
Well..."unusable" is a pretty extreme quality rating. There's a long way between the "perfect" mic for a given situation and one that is "unusable".
You can make a lot of mics "useable"...or you simply accept what they have to offer, and you make that your "perfect" choice (because you have nothing better)...but it's not the same as using a mic that fits the situation perfectly, even if it is not the perfect mic for everything.
I also don't think it's just a matter of "EQ" that lets you make any mic suitable. Lots of folks have spent hours trying to "EQ" something into an acceptable sound, and it simply didn't work out well, or they were forced to accept it to be "as good as it gets".
With the right mic for a given situation...EQ becomes some icing on the cake, not a fix. So I wouldn't use say...a ribbon...and then try to EQ it so that I'm getting something that sounds like it was recorded with the LDC...or vice-versa.
Like I said earlier...I don't think it's really important that you or anyone can tell what mics were used on some recordings...there's no value in that information from a listener's perspective...but from an engineering perspective, you want to select the best mic for whatever sound you are after or that works best with the source.
Many of the old-school recordings (and a lot of new stuff too that follows that mindset) just have that cohesive sound quality, and there was little signal manipulation done after the fact to achieve it...again, more like just adding some icing to a cake...because it had a lot to do with mic selection and positioning, and balancing things during tracking. I know modern Pop doesn't use that approach, and you can still get stuff that sounds pretty good...but often, IMO...it's a more "fabricated" sound...and mostly done ITB without much tracking, so mic selection was minimal...probably mostly to do with the lead vocal, and then even that got manipulated heavily.
I was just reading the article in the latest Mix issue where they have Lady Gaga on the cover...and the article is about her new album.
I'm not much of a Lady Gaga fan...I could hardly name 3 of her songs...but I like to read about the studio process even for music I don't really listen to.
So they were talking about her vocal treatment (she has an engineer who only does her vocals...someone else does the rest)...and they talked about "capturing that unique voice" (TBH, I don't think her voice is all that unique)...and then they go on to say that her vocals guy has an "extensive vocal production/mix template of 60-plus tracks"...that's just the vocal!
When you think about that...you could almost say it's not important what mic she used...they're going to beat the piss out of those vocal tracks with processing anyway...plus they have like differently processed vocals that are changed from verses to chorus, phrase to phrase...and maybe even word to word...which is the thing with Pop productions these days. It's all about "sound design", and less about tracking live performances.
That said...when it comes to more old-school, organic kind of vocal (and instrument) tracking and mixing...much of it is set during the initial takes, so the mics really have to deliver what you want/need...which means there has to be some deliberate selection...rather than trying to make stuff useable through manipulation afterwards.
Anyway, that's my interest these days...getting like 80% of the sound during tracking...well, at least that's what it will be when I get this studio finished.