Yes, true -- and is why I find the brisket in Texas so uniformly lacking in flavor. After eating at literally dozens of Q spots in Texas I cannot say I have ever had brisket that was truly remarkable in terms of flavor. Tenderness, yes; flavor no.
Paprika does not have much flavor to begin with and what it has cannot stand up to long cooking. Cayenne has heat but virtually no flavor. So essentially you end up with salt, pepper and some heat which, yes, is typical of much Texas brisket.
The notion that beef needs to be treated delicately -- like it is chicken breast or something -- is utterly without merit (it's beef!) and betrays a lack of knowledge on the part of the cook. If someone wants to cook with salt and pepper alone fine, who am I to judge? (But don't invite me to dinner.) A rub can have 50 ingredients or 5. If it is overwhelming then that is the fault of the cook, not the beef --which can handle quite a bit of flavor additions if they are combined skillfully and -- and this is important -- applied with a judicious hand.