Dude I have a 13yo boat with one of the graphs I bought used and the other I was able to afford due to the rebate. Also I sold my current graph to get it and that only put me out about $300 to upgrade from my 998 to the 999. If I was all about the latest and greatest I'd have much more than two midrange graphs on my boat. My budget doesn't allow it.
To counter your statement about guys into electronics someone I consider to be one of the best tournament fishermen in the area proves that statement dead wrong. I will not name drop but I'll say he did well at the all American this year and has been solid for a while. A few years ago when I was considering my first unit (898) I asked him what he thought about side imaging. His words were that he has cashed many check due to him having it on his boat. Finding brush, ledges, rock piles isolated lay downs etc etc etc is inarguably easier with si. It's about isolating your time to productive water when you aren't beating the bank. Same story with a couple grand lake gurus I know. Yes it's neat to tinker with but it's also productive and a learning experience. Again with one of the very best fisherman on Stockton. He applied si and got serious about it and now he's the guy to beat post spawn.
So maybe wrench is right that he doesn't know anyone that can run s graph and fish good. I'm not surprised really.