:: summon your Path Companion in regional levequests (solo mode)

[Randis]

And you can, there's nothing that's stopping you from doing so. But anything that actively promotes solo play at the same time discourages group play, something that should be avoided. You can always solo, but you need other people to group.

That is a poor argument. Those who prefere to play solo will do it regerdless, you cant force them to party with you.
Try to see the things less black and white please. There are people who DO play in parties but also want solo time.
I have a lot of japanese riends and i can see why so many people there choose to play solo.
Many of the people i know work 6 days a week and come home late evening almost every day, some can only play longer on weekends and that is when they usually meet up with LS buddies to have fun but people sometimes also just want to play for half n hour before they go to bed.
You can not expect them to team up or looking for a party every time they want to play and you cant deny people fun.