I wonder if that isn't either sales talk- or a local phenomenon? On the East Coast, 24' is the sweet spot, and the minimum the oval track boys will consider. I think I've seen RVs with longer than 24' trailers-- but at least that size. I imagine there is no max trailer length, but rather a max overall length for both the RV and any appurtenances, so this would be something that might vary by RV size?Just had an interesting conversation with the local (east of San Diego) Haulmark dealer. He says don't buy anything longer than 22' for resale becasue 24' is too long (legally) for a full-size RV, and that those guys are the biggest market for resale. Also, that full-size RV resale consideration calls for an extended tongue. I wonder if this is a SoCal thing.
Given that, maybe I'll just assume I'm keeping it forever. I stood in a 24' and visualized my 14' car at the back. That 10' open floor space in front sure looks huge. OTOH, a 20' trailer leaves only 6' which seems too small. So resale aside I'm thinking 22' looks like the goldilocks "just right" size.... ??
Also learned that the "Edge" model was just "unbundled" so all the racer stuff (power, cabinets, etc.) is extra cost now. Overall cost is about the same though, just a lower entry price.
Remember that the car will normally need to be centered (more or less) over the axles, and so you likely won't have 10' of open space in the front, but rather some in the front and some in the back.
If you are really buying it forever, I still would suggest that few people have been heard to head to the track saying "Gee, I wish I had a smaller trailer."
A longer trailer may be harder to park and tow, so perhaps the local dealer will let you hook one up and drive it around for a bit to get used to the length. Try a couple lengths so the first one doesn't put you off if you haven't done this before.
My 20' was perfect for my needs, but when it came time to sell my "lifetime" trailer, many buyers passed it by for a lesser, but bigger trailer. Just my 2 hex bytes.