I get a truck 100 years ago is very different than a truck today. Same as an airplane, car, home, etc. I live 3 minutes from a waterway where it is all water sports and fishing; 22' limit, jet ski's and tubes are banned...the fishing guys stay in the no wake and everyone else is doing water sports. I've never, ever seen an old jet boat, Chris Craft, etc. For ski boats, it's Malibu and Mastercraft inboards with a Ski Natique 2001 thrown in. Then you get a couple of I/O's thrown in usually knee boarding, a pair of skis or doing some weird and inappropriate things with a surf board. Even the Yamaha Jet Boat guys don't come out much.
In the last 30 years, direct drive inboard is a ski boat. Period. Hell, I don't even ski a direct drive - my boat is one of the best Vdrive boats to ski behind (SV23 diamond hull Malibu), and to be honest I only slalom a couple times a year behind it - the rest is surfing with a bit of wakeboarding thrown in (and perhaps wake foiling this year if my wife wants to go even bigger on this year's Father's Day present, as last year was a $1000 surf board).
I'm also pretty sure the OP was referencing a freaking I/O runabout as a ski boat. I/O's are for Wally's, not folks that are into water sports. Now a proper footing boat with an outboard, like a Malibu Flightcraft, that's a whole other animal, but even lighter than an inboard ski boat.