In most cases, drummers are hired guns, and are brought in to play the songs, not to further the art. The drummers who don't know the difference won't be working much, and that applies to any point in the artistic spectrum. The pros known when to turn it on & off, which is why you always hear them playing the right parts, regardless how mainstream or adventurous the artist is.
I think you and I are agreeing on some level. In a hired-gun scenario, you can get by with a minimalistic kit and sample pad. On the other end of the spectrum, you would have an "analog analogue" of each instrument you need to represent. To me, the balance between the two is determined by means (logistics, financial, etc) and artistic vision (can you make an actual/real
rainstick entertaining?). Put another way... Do you push a button on the pad, or do you Cirque-Du-Soleil the shit out of that triangle.
An aside:
When we're on stage as performers, anything you do to fill your idle time and bandwidth for the sake of entertainment/art is desirable/encourageable. In some cases, it can be a costume change. In other cases, it can be dance, choreography, backing vocals, etc, etc. The guys with huge stage setups are just doing the same, but with additional instrumentation.
When we were signed in the 90's, In addition to guitar and vocal lessons, I was pushed into college level dance, choreography, public speaking, etiquette, stage, music, and set design. At the time, I simply was enjoying the freedom being a 16yr old at college. I thought the classes were stupid. Then I learned enough to recognize when other entertainers were using the disciplines.
Re: Two laptops = Hot failover.
You have the time between songs to fail over when your kit goes titsup. There are 40,000 people watch you. Ready, set, go.