Basically. Although i might argue that Madonna might be bigger then Brit WW. MDNA has sold 1.3 Mill without any hits whilst Britneys album sales were bleak with a couple of hits on her last album.
It's definitely not Britney> Gaga anymore. That's a fact, however if we are talking about when she was at her peak then possibly yes. I still don't remember hearing about Britney doing these huge ass tour numbers that Gaga is doing now though and WW. So I can't really even say so for sure.
I'm gonna say MJ>Madonna>Gaga>Britney
The touring market in general wasn't anywhere near as big as it is now at Britney's peak.
