That's a sad story...
Unfortunately, it's hard to get beginners into on-road. It just isn't beginner friendly. All the hardcore equipment, high dollar cars, adjustments, angry, uppity experts, etc, etc...
And the current "Slash" of on-road? M-03/05 minis perhaps..but out of the box performance of 15 mph (if that) is hardly enticing to someone shelling out a couple hundred bucks at least to get into it. Or maybe you want them to start with E10/TT-01 type kits...but race with whom?
See how off-road is so much more enticing, with 25+mph* right out of the box? The Slash is durable too. Try taking an M-03 or E10 or TT-01 to 25-30mph and see how long they last...ok maybe a while, but you get my point...