Of course results will depend on a number of factors including: variety, growing zone, maintenance ie. pruning fertilizer, weeding, watering habit etc... That said, I grow them without a trellis and get plenty of fruit. Only about half of my canes are fully erect, and the other half lean or droop quite a bit, but it doesn't bother me as long as they don't touch the ground. Sometimes I consider getting a trellis because it would make the patch look tidier and the berries may be a little easier to pick. I've noticed that the new canes have improved over time, compared to how they grew the first couple years. I also tip mine at about 30" to make them bush out and prevent them from becoming too lanky.

I grow mine a cattle panel/T-post set up, but truthfully I don't think they need it -- I grow "Caroline", her canes stay fairly upright and supported by each other. She gets cut down in the spring (primocane type), so maybe that makes a difference - not sure.

Thank you both- I'm more and more tempted to try simply removing the trellis.