I know that's right! If I grew 2-3000 plants a year I would be changing up alot of the things I do, starting with hiding my scissors!
Clipping tobacco plants certainly doesn't hurt anything. That's a given. But yes, I see it as a lot of time spent for little to no gain for me. One year I had almost 7000. But I was younger then. Never again! Too many for me!
I've seen BigBonner's set up with the lawn mower set over a roller table so he can push float trays under it in an assembly line process for clipping. But he grows 20-30 acres or more and uses machines to plant. At 6-7000 plants per acre, well you can do the math. That's a lot of plants! And in a big greenhouse set up with float trays it has other advantages too. Like the even application of pesticides if needed. So he needs the uniformity clipping provides.
Getting root bound has a negative effect on any plant. I start all my tomatoes so I have 7-8 week old plants to start selling on Mothers Day. That's the perfect size to sell and set out. And Mother's Day is a huge selling weekend if the weather is decent. By nine weeks they start to get root bound in a 3 1/2" pot and the plants sense the change. They go from a vegetative growth stage to starting to bloom because they think that's all they will have to work with. I usually pot them up to 1/2 gallon pots if I haven't sold them all at this stage and raise the price on them. A bigger pot and extra soil means extra costs in materials and labor. But for the ones I plan to grow myself, they all come from the last batch I start so they are no more than 8 weeks old when they go into the field.
If you set out root bound tomatoes that have flowers or have already set tiny tomatoes, they will switch back to the vegetative growth stage. But it take them 2-3 weeks to fully do it. 7 week old plants that weren't root bound will pass them up before the older ones switch back to vegetative growth again. I've done this with different aged plants set out on the same day side by side. Eventually the older ones catch up but the younger non root bound plants do the best.
I tell people this, but people are funny. They still want the ones that already have flowers and little tomatoes on them. So I just smile and sell them what they want.