Don't ask me to explain why you can't get in - I'm not on the phone with Yoshi and I don't think he'd have the time to look into individuals. I disconnected at something like 8pm on a weekday and got back in immediately with a queue of 18. Perhaps a lot of people in America are staying up late on Sunday night playing the game?

As for sources...

Yoshi, in his "Further Details on Access Restrictions" post in General Discussion of the official FFXIV:ARR forums...
Quote Originally Posted by Yoshi
The restoration of crashed servers is usually followed by a rush of players attempting go log back in, which, in turn, puts a straing on our lobby server, and can ultimately have an adverse affect on all of the Worlds.

To prevent this from happening, we felt the safest course of action would be to limit logins.
This is why you get 1017 at all. They limit logins rather than putting you in a queue that might never end because of the strain such an unlimited queue can cause on the lobby and subsequently other worlds.
Quote Originally Posted by Yoshi
However, we would like you to know that the restrictions are under constant surveillance. We are currently monitoring login numbers on all Worlds 24 hours a day, and actively removing/applying restrictions as soon as we detect even the smallest fluctuation in concurrent connection numbers.
...so, monitored 24/7, as I said. If they feel they can let you in, they will.
Quote Originally Posted by Yoshi
In addition to increasing the number of Worlds, we are also optimizing the Duty Finder (party matching) management servers in an effort to reduce server load and ensure better stability when using this feature.
Here he acknowledges that the Duty Finder is a problem, which pretty much everyone and their uncle knows if they look into the problems that the servers have experienced and looks through more of the dev posts. Seriously, dev posts are great.
Quote Originally Posted by Yoshi
From several users on some of our more congested Worlds, we have received requests for a feature which automatically logs out characters who are AFK for an extended period of time. We are actively looking into the implementation of such a feature, but have decided to first concentrate our efforts on increasing the number of Worlds and optimizing the Duty Finder servers.
This is where he says that the Devs feel that the overall number of worlds and the Duty Finder servers are more important than an auto-afk-kick.

Quote Originally Posted by Aulayna View Post
The issue isn't just related to the duty finder anymore it's that servers can crash if there are too many people in densely populated areas - such as the starter areas, which is why they had really limited capacity at the start and have gradually increased them as the population has spread out across all areas. Even if you are on the server doing nothing you are still consuming resources that is preventing someone else from logging in.
The resources being used are absolute bugger all compared to the resources that would be used by an active player. Like... less than 1% of the resources. Going by what has been stated in Zach's link where a bunch of server admins for similar games are posting, the amount of resources used by someone in a small area single-character instance are tiny compared to someone through Duty Finder. I wouldn't be surprised if one character in the duty finder would have the same cost as hundreds of users in their inns doing nothing. And again, this is the only way I can get friend requests. I dare say there would be around 10-20% fewer people in our LS - perhaps even 30% fewer - if I couldn't receive friend requests. No afk = No friend request = No LS/FC invite. I know we have other leaders but they aren't always online and I'd much prefer the simple ability to add friends who are offline, have them accept when I'm offline, add them to the LS/FC when they're offline, etc. etc. This would go a very long way towards me altering my opinion on AFK'ers. I do agree that AFK'ers in the cities are annoying, though - that's why I insist on returning to the inn.

Oh, and there are still issues with the duty finder. The "stories" haven't stopped - the lower caps on server population are a direct result of the resource-intensive things such as (as you stated) the starter areas and (as I've mentioned) the duty finder. It's repeatedly mentioned by server gurus walking the forums and, it seems, reddit that the duty finder is a massive resource hog. I mean, think about it - they're adding a few more worlds, right? They have 25 servers and one duty finder covering all 25. If they add a few more, they say this will create a need to split the duty finder for the data center. Now, if you were to split those few worlds' populations amongst the existing servers, that would cause a similar problem for the duty finder (as it's the same total population regardless of being spread over 25 worlds or over 28 worlds). Therefore, it's a reasonable conclusion that the duty finder is still restricting the world capacities.
Also worth noting is they haven't ruled out kicking people who are AFK. They have openly said they are considering it but are waiting to see what the situation is like after the hardware upgrades this week.
They're actively looking into it, which is a shame because it's clearly just to pander to the masses and won't actually have any huge benefit. If anything, it could have an adverse effect in that of the servers which actually struggle most - the lobby and the duty finder - the lobby would actually have an increase of activity. This is the main reason I think they're not prioritising it, actually. Think of all the information required to log in (more than you might think) compared the information required for a character to idle in their inn.

I'd happily have them afk-kick anyone who idles in the busy areas, though.