This is not only the territory of dubiously useful counterfactuals, but also doesn't square with the actual history of the day.
Some of the faults I see with this way of thinking:
A. The pieces of modern 'combined arms' forces, like tanks and war planes, were not advanced to the point where they could achieve the 'combined' part. The entire reason why these weapons work so effectively in modern doctrine is that they operate together with infantry. Tanks of this era were brand new, extremely experimental weapons. They moved at the speed of a 100+ year old tractor. This is not a weapon yet capable of being deployed en masse and just winning the war like that.
B. To suggest that these weapons were 'capable' of winning the war, but just weren't deployed correctly or in enough numbers is to project incompetence on to military leaders of the past. Clearly they did try these things, and they did not work. There was no reason to expect that if tanks with 1918 level technology didn't achieve much success, then they should have just tried throwing more at the equation, or to expect modern combined arms doctrine to just spring out of their minds fully formed.
C. It's been touched on in the (very good) original post, but the land of the western front, torn up by artillery and barbed wire, was not the suitable environment for mechanized warfare to be developed. Doctrine can't spring forth from nowhere to solve a problem. It has to accompany these changes in military technology under conditions that allow commanders to experience what this technology is and isn't good at, and 100 year old trucks were certainly not going to be great at blitzing across crater-strewn Flanders.
D. You suggest this all may have been a matter of no ready-to-go industry existing for these new weapons. I would argue that if there was ever a thought they had a solution involving these tools, the massive armament industry of WW1 could easily have been brought to bear upon making them.
Now I am really, really far from a military aircraft history guy. So I don't feel super comfortable commenting on the air theory, but from my limited reading I believe the problem to be one of engine design and general new-ness of these things as weapons themselves (just like tanks).
The Wrights flew their powered plane in the end of 1903. WW1 is almost exactly 10 years after that. Again, it is unreasonable to expect the technology to be at the point to support modern doctrine. These were brand new, and engines were simply not both strong and light enough to create the kinds of war planes you'd see in the next 30 years.
To summarize though, again, I think the most salient point is really just that people of the past are often not as illogical about these things as you might expect. They wanted to end the war. If there was even a sliver of a chance of any of these weapons being 'the' breakthrough, they would have pushed the technology as far as it can go to find it. The fact that they did not, is evidence enough. If the solution was simple, it wouldn't have been a stalemate.