Amps will be with us forever I think, well at least untill transducers become absolete
Yes there are a lot of powere PA enlclusures these days, but they are marketed and intended for nothing much bigger than a bar. Sure there are a few companies pushing small venue systems, but for every 1 put in 10 are done with powere amps. The Power amp method while being a bit more cumbersom is more customizable and in my experiance reliable. In the world of major tours and huge installs, system design is a critical step and quite often is planned down to the minutia. Powered PA's just don't offer that, way more of "stick it on a stage and play" mentality. Plus a good PA running nice and amps and speakers, crossed over properly sounds way better anyhow. Also ever notice how some of those powered enlcosures, Mackie, anyway have a pretty high noise floor?
