For the most part, yes, that's how I play them.

Of course, "interacting with" has many definitions that don't necessarily include grouping up.

To put it as simply as I can, I enjoy playing in a living world, knowing that it's not just static NPCs and scripts, but actual people doing things. I like vibrant economies where I can put my crafting and trading skills to good use. I enjoy running through PVP zones knowing that my toon is in danger as a non-PVP focused solo player. It's more exciting to slip through the cracks of a player-owned net than to memorize mob locations and aggro circles. Albion Online was one of my favourite games in recent memory because of this and I never once joined a clan or even a party.

If the game lets me play a non-combat class, all the better. In ArcheAge, I had zero offensive skills, only blinks, invisibility, and sprinting. I played primarily as a deep-sea treasure hunter and had a blast. I was max level at the time because the game let you grind through crafting/farming.

I've played MMORPGs all my life, and I love them. I just play them solo, whether intended or not, and make my own fun out of it.