First of all you're gross for using her kids in the middle of a 'shade?' Though, you need to try harder cause that was weak as sh_it and extremely predictable, but am I expecting more from a pressed Screamtina fan? Nah!
Second of all, since when this is a competition between a career and personal life? Again, gross.
Also, Britney may not be Mariah or Whitney when it comes to vocals (and I assure you that nobody ever said that) but she has a very unique tone and it's very iconic, period. Not to mention that Britney never claimed to be a singer, she's a performer and even though she doesn't have a powerhouse voice she was and still is able to outsell all her peers so, yeah try harder babe.