I find it unlikely, for example that there would not be a dominant centralized forum platform. People would have certainly started problematic communities on the dominant platform, and it's unlikely a platform with strict moderation would have gained dominance before 2015 or so. I do think a dominant player would have been established by 2015.
Do you think whatever you see as harmful about Reddit would not have occurred if the company didn't exist?
The corporate shield for accountability is so annoying in this way. Nobody’s ever responsible for things that they did as human beings.
They thought it was a social bookmarking thing for people to find and share blog posts. It didn't even have comments for the first half year. For two more years, self-posts only existed as a hack where the poster had to predict the post's ID to make it link to itself. User-created subreddits didn't show up until about 2.5 years after the site launched.