From my perspective , a guy without zooms has made a decision. "There are certain shots I'm not going to get, in order to maintain absolutely optimum image quality." You simply cannot carry enough zooms to adequately cover the range I get with my 8-16, 18-135 and 60-250.
SO here's what happens you need 120mm, but you only have 100mm and 200mm primes. So clearly you have to shoot with the 100mm lens and crop. My 60-250 is already equal to what you're going to get with the 100, but now you're cropping 20 %. SO in terms of resolution, you are getting 20% less lw/ph compared to my DA*60-250 image, yet, you are thinking that you're getting a better image because you are using a prime.
I would suggest, you only get a better image with a prime if the best framing happens to coincide with the primes field of view.
Look at the following sequence of images. They are taken within three minutes of each other at 4 different focal lengths at a time when the light was changing constantly. For this type of image, you can have a very short window during which the light is the best. The entire sequences is taken within 3 minutes. Short of having a "boy friday " to hand you different cameras with different focal length primes, I'm not sure how you even accomplish this with primes, and before zooms were good, that's what people did. There is one photo taken in the 22 minute, 2 each in the 23 and 24th and 3 in the 25th. Lens changes would both result in missed images and or lower IQ in most of the images. The images are also shot at 4 different focal lengths. That probably would have extended the time spent a this location and reduced the time I spent at other location nearby.
I hear the "primes thing over and over again... but personally, I just don't get it. There will be few images where a prime gets you a better image where a zoom would. There will be lot's of instances where you end up with no image at all because you had the wrong lens on the camera. And there will be lots of images where the zoom is just as good as the prime.
I always shoot zooms when timing is critical, and primes when i have time to lallygag around and fiddle about... but that is rare. I hate missing a great image, because I had the wrong focal length prime on my camera.
I work from the premise that, the first image I see is not always the best, the first focal length I choose is rarely the one that works out best, often I see an image within an image while taking a photo. I take the shot, and then , if I have time, I look at the focal length to see if one of the primes in my bag will cover it. If it's at 24 for the 18-135 or anywhere on the 60-250, I won't even bother. I've taken these lenses off the camera often enough to know, there are focal lengths where a prime isn't going to ad anything.
My experience would be, if you're shooting primes only, you are missing a lot of great opportunities. You can see there are 3 images in the sequence I looked at, thinking of printing them. How many would there be if I'd taken a couple minutes to change lenses? It's quite possible that the instant those images were taken would have been missed, because I was changing lenses. There is a reason why so many pros rely on zooms these days.
And to top it off, because, I was only 4 minutes at this location... I also got this, at a nearby location.
And this...
and... well,you get the point.