people can do all of those things with groups

People take conference calls with other people all the time. So much so entire companies have been built around the idea. Sitting in front of a computer to video chat with other people is hardly isolating. Plus computers can be used while others are present.

Movies are watched with other people present very often.

Again, VR is the only thing here that isolates you and literally blocks you from your surroundings, nor can anyone else see what you're doing.

Lots of PC gamers play with headphones on, fully immersed in the onscreen play. You can use VR in groups as well. The most popular VR applications are social, like VR Chat. VR can also be broadcast so that others can see. When my family plays BeatSaber, it's almost always in a group where others watch, keep score, cheer each other on, and take turns, much in the same way people engage in RL sports, like horseshoes. MR even blends RL and VR.

You would do all of those things in a vr environment.

Have a video chat while in vr. You can appear and feel as if you are sitting across a table.

Conference call in a virtual board office.

You can go to the movies with someone from anywhere in vr. It makes the perfect safe first date.

Shared VR experiences is the future of VR.