But that's a separate gripe from huge gameplay changes in PoE2 that just seem to amount to the devs repudiating their own legacy and philosophy and going, "Let's copy X popular game that has no connection to ARPGs!"
Well, at least they've separated games so there won't be giant backlash at the release or open beta
Incidentally, I believe this is the reason they won't increase drop chances for SSF. I'm not sure it's the reason for the trade thing though, because they could just adjust drop rates to reflect the new, cheaper economy.
The game is already very unfriendly for non-solo play (shared curses limit, incoming damage is increased way more than shared buffs increase survivability and DPS (sans aurabots)), so if the drop rates were much higher in SSF, why even bother with trade unless there are hard to get items like MB, HH, good rolled synth items, oriath end etc. Although they could have tried at the very least experimenting it (actually, they did with harvest which allowed to plan upgrades in SSF, but it was deemed too powerful for trade leagues)