I don't think your statements are correct.
Anyone who goes to reddit.com sees only default subreddits, whether they have an account or not. You only see all subreddits if you specifically go to reddit.com/r/all. Again, you see all subreddits there whether you have an account or not.
Some people say that /r/all should be the main page for everyone, and that defaults are an unnecessary and even undesirable filter. However, the problem with /r/all is that it includes a lot of NSFW content (if you have an account) and a lot of highly specialized content from communities that are very active but not general interest (things like League of Legends, polandball, etc.).
Default subs seem like a flawed but necessary compromise, though maybe not the best one.