Compound turbos

I think the idea of compound turbocharging is such a good one I'm really surprised why more people don't do it. Especially on high horsepower cars. I think the idea of it is applied to 1000+whp cars which would normally take a long time to come on full boost with a big single, but a compound turbo kit can spool around 1.5 bar from just 2800rpm, with full boost usually achievable way before 4000rpm. Is there a reason no one uses them, especially on a Supra? Is it just simply much easier and cheaper to whack a single turbo in?

I know Titan Motorsports sell a compound kit (http://www.titanmotorsports.com/bolosucotuki.html) but there's only a couple of 2JZ engines I can find on the internet running compound turbos. They sound sweet as well

Been tried before, quite complex and expensive. More suited to Diesels

Not really needed with the turbo technology we have now

As above, with the advent of relatively high compression, direct rail injectio turbo petrol engines, with modern management lag is a thing of the past, pretty much.

Compound turbo charging works best on diesels as they generally run a constant wide open throttle and control engine power by fuel. For reasons I forget this favours compound turbo charging.