While I do agree with everything you say, it's just that not everyone can spend 40,000$ to get optimum results. Also, if you own a 13,000$ telescope (your 600mm lens) Why didn't you get a high precision EQ Mount?
Oh yeah, I'm not saying everyone can or even should spend that kind of money. Just saying that if you want to get great quality, it tends to cost a whole lot more to get it with astrophotography than it does with normal photography. With normal photography, if you have the skill, you can get very good results with fairly minimal gear. The gear matters, but not as much. With astrophotography, the quality of the gear has rather exceptional importance, which makes it a very (saddeningly, even) expensive hobby.
I do plan to get a 10Micron GM2000HPS UP mount. It's a $20,000 mount, one of the best (personally, I think it is the best...at the moment, 10Micron is the only manufacturer that has moved all the sky modeling right into the mount. The other high end manufacturers like Astro-Physics or Software Bisque still have all the modeling in software, that has to run on a computer plugged into the mount.) I haven't gotten it yet because, the obvious reason, it's ridiculously expensive.
I just bought my 600mm lens less than a year ago (summer last year), and I still haven't really recovered from that expense.
The other reason is as much as I'd like to have it now, I can still learn with the ~$2500 worth of mount gear and my 600mm lens. Before I invest in a 10Micron mount and even an Astro-Tech AT16RC Truss (which would be $27,000), I want to have more skill. Acquiring images is only a small part of the process of producing great astrophotography images. Since you do astrophotography yourself, you surely know this: Processing is at least half, it not more like 2/3rds, of the art. I might spend six to eight hours acquiring images, which really involves about 2-3 hours of actual personal time invested (the rest is just the mount and imager and guider doing their things on their own.) I can easily spend a few hours sifting through my subs, picking the good ones and culling the bad ones and finally stacking, then another 10 hours at least of processing and tweaking and fine tuning my images in PixInsight and Photoshop. I've revisited some of my works two or three times, trying to get better results each time. In my Rosette image, I've probably got 20 hours of processing time in. I just started revisiting my Monkey Head image, which has at least 15 hours already, and I think I'll be spending at least another 5-10 hours on it to get noise levels down to an acceptable level and lift up some of the dimmer nebulosity.
Given that so much of the artform of astrophotography involves everything that comes AFTER image acquisition, I decided I should get good at that first, and make sure I am even capable of achieving the skill level I believe is necessary to produce Robert Gendler or Russel Croman level images...before I dropped $30k or more into more equipment.