Yes and correct. I will assume 5 volt logic. For Q3, the Collector voltage range will be 0 - 4.3 volts. For Q4, subtract this voltage from the supply. That means with a 24 volt supply, the Collector voltage range will be 23.3 - 19.3 volts. (Correct me if I'm wrong guys).
This is why we say it won't work. It's not a switch in that configuration (Q3 and Q4) - it's a current amplifier. Q3 might do something. Q4 will be on all the time.
If you are planning to add a second transistor on the output of your sensor to invert the logic, then it might work because you will have 24 volts for the base voltage. You still need a resistor on the base. The voltage difference between Base and Emitter is ALWAYS .7 volts (for silicon transistors). This important rule alone should make it clear why Q3 and Q4 won't do what you want.
Also, your drawing are Theoretical for a switch. When someone gives an example for a switch, they show one transistor. In actual practice, 2 transistors (in one package) are used. I'm not sure what would happen with Q3 and Q4 if they were Darlingtons.
OT,
(Ron, sorry if I put you on the spot Buddy. You're always good at providing great detail.) I suspect this is being translated into Arabic, so I am trying to be careful with the words I use in case he is using an automatic translator. Those really can make technical English hard to understand.
Maybe if we say it enough ways, it will sink in.