I/O to Inboard?

My dad purchased a brand new '07 Stingray 19.5' I/O family bowrider this spring ($24K). We'd owned a 1995 Caravelle bowrider previous to this and HAD spent most of our time on the water tubing and kneeboarding. I've become hooked on wakeboarding since the new purchase and the rest of the family mainly skis. We haven't used the kneeboard or tube in the last 35 hrs on the boat (we've put on 75!).

I've always heard that inboards are much more reliable than i/o's and cost substantially less to maintain. From my dad's perspective, he wants a boat that will be very reliable and will not cost a fortune to maintain. (He's not as interested in the size of my wake.) From a financial standpoint, would it be cheaper to sell our i/o for say $21K and buy a used wakeboard boat for the exact same amount? What brand/model/quality boat could $21Kish buy me?

Thanks!