Dude, no reason to get so upset. I’m sorry your clients aren’t impressed by your sketches. I haven’t found that to be true in my case. I have a few clients that have some of my early process sketches framed on their walls, sometimes from a decade ago… this is not a bad thing.
And you are totally right, practicing making things is helpful, and I could do more of that. That is where I usually contract out work where as when I was younger I did a lot of that work myself. Now anything beyond a quick mockup to see if something might work or a print out of a tightly controlled curve to scale goes to one of my guys. To rationalize I suppose I have decide where to invest time… but the ask here is about sketching specifically, and the answer is still the best way to be better is to practice.
No need to degrade someone else skill as a party trick. Obviously I’m not going to be giving away tons of thinking for free on instagram. Just showing 30 minute warm ups. I get paid to design a lot of sneakers and cars (among other things, been a recent uptick in medical due to the consumerization of health and wellness), so I save the thinking for the clients.
Of course a good sketch doesn’t equal good design, but it doesn’t hurt it either. A great idea not selected because it wasn’t represented well is useless.