The other thing about up-potting or just growing in small pots is that as soon as a plants roots begin to circle the container they are in the plant is then under some degree of stress.
The longer you allow the circling to continue the worse the stress gets and the more problems you will be likely to face.
　
If you up-pot several times you risk additional risk for multiple stressful periods that could easily be avoided.
You also run the risk of damage every time you handle your plants.
Then you also need more sized containers and either toss them out and replace them if things like cups or have to store more things when unused if actual pots and of course you do have to pay for all of that.
I hate to disagree with your points, since I have a lot of respect for you and have noticed that you consistently post good information.
However, I personally don't agree that the circling of roots causes stress, at least not for a long time. I keep bonsai mother plants in small (4") pots, and they consistently produce good clones and show no signs of stress in themselves.
I root trim every few months to encourage growth spurts, but they are extremely happy up to this point, even when the pot is full of roots. Growth is inhibited somewhat by small pots, but it does not seem to cause the plant a great deal of stress, as long as they are still fed properly.
As far as transplant shock is concerned, i've never experienced it myself, possibly due to my potting up technique (
details). I also think that most root damage caused during transplant is down to people transplanting too early, before the establishment of a proper root mass that will hold itself together properly.
It is true that it is an extra set of pots to buy and store, but as a one-off cheap purchase, it wasn't really an issue for me.
It is true that incremental pot-ups will add several days to your veg cycle, but for me the benefits are worth it. I'm not saying everybody should do things this way, but it does have it's benefits, as well as it's drawbacks.
