Rounding out your cost to the nearest $5-10 can make sense. Especially when it's an exact amount like $23 I'll give them $25 because it's just easier, but when you say tip the common amount of a tip is 15-25% would have you tip $3.50-5.75 on that $23 haircut. That's more than I've ever tipped them because I'm already paying over $20 for something they completed in ~20 minutes without using anything that would cost them money (other than time).
Paying for the experience is not what I'm paying for, I'm paying for the service. Going to the movies I don't tip the concession stand for providing me with the "movie experience" when they give me popcorn. And anytime they do extra stuff like shaving my face it costs extra. The haircut costs X amount and anything extra adds Y amount, it's a service the same as all other services.
You are correct in that typically hair salons and barber shops will rent out the chairs to barbers, but this is done in 1 of 2 ways typically, the barber pays per month and they keep all of the money they make, or they pay a portion of every customer. Why does this matter to you as the consumer? If the barber isn't making enough, the prices can increase. My local barbershop increased prices 2 times in the last 4 years. If they're supposed to make their money on tips why is this? Their costs to run the business haven't gone up because they don't use anything to perform the service, so it must be to pay the barbers a better amount. Something that wouldn't happen if it's "meant to be a tipped position".
Yes, and my question is why is it standard, why should it be done? Just because something is standard doesn't mean it makes sense, could you explain why it should be done?