Yeah, I think you're talking about two different effects. I don't believe any of these games that you're showing me are entirely locked up with no chance for progress. However, these are game in which there are locked-in alliances, both sides could make progress if they choose to put their efforts into attacking, and the larger power would get rolled back a bit, hence the draw.
If you want to turn a game like this into a solo, it has to begin far earlier. Once you have a three-way game with no immediate winner, it's almost certain to be a three-way draw.
Maybe this is the most useful advice I can give: I've never soloed without my opponents choosing to let me to do so. This should be obvious to you -- you can't even make it out of the early game without your opponents choosing to let you do so. You've probably learned by now that the way to accomplish this task is to convince your neighbors that it's in their best interest to let you grow, right? And of course in the game that you end up winning, they made a mistake by doing so. The key to getting a solo is creating conditions where your opponents will make mistakes that give you a solo. There are several tricks for this, depending upon the position, and maybe this thread isn't the best place for that discussion anymore, but it's probably instructive to consider the advantages and disadvantages of being the attacker.
Disadvantages:
- It's obvious that if you are not stopped, the game will end in a solo win for you. Therefore, players will all want to make stopping you their top priority.
- You have fewer total units than the defenders (since otherwise you'd have a solo already)
Advantages:
- Your units are always 100% coordinated, while the defenders cannot coordinate in gunboat. Even with press, the defenders often disagree on a unified plan while your units will have one. This means, for example, that it's very difficult for opponents to hold a dynamic stalemate of the sort that often is necessary around Berlin on the standard map.
- You can put any unit on the front lines in any spot, but a coalition often cannot because it would involve putting, say, a Turkish army into a Russian supply center to try and hold the line. The recent SoW gunboat game has an example of this.
-- Your units are presumably all built for the purpose of pushing for a solo in a long-term plan, but the defenders often have the wrong units for the position. The recent SoW gunboat game is a great example of this -- the defenders have far more fleets than are needed in the Med, because Italy and Turkey had been fighting, and as a result have too few armies to hold a line. France, on the other hand, had the right fleet/army balance to make every unit useful.
- If there are a large number of defenders, some of the smaller ones will be worried both about holding a line and about doing so in a way where they cannot be eliminated once that line is established.
- There is usually residual mistrust in the defensive coalition which might mean they cannot make completely efficient orders in the first couple of turns after it forms for diplomatic reasons.
- Any individual player can make a mistake. The defenders have more players than the attackers.
So, if you want to get more solos, what you should be doing is to think about ways to make as much use as possible of those advantages, and ideally be thinking about setting up a good situation well in advance of the point that the defensive coalition forms. The maps that were mentioned here are maps in which there are only two defenders in the coalition, each has a decent set of units for the problem, and each has an independent part of the line to defend so that relatively little coordination is needed in order to hold off the attacker. Even so, I'm not sure it's a 100% line, but this is as good of a defensive situation as possible. So, the best way to achieve a solo on those maps would have been to try and complicate the situation several game years earlier, ideally keeping a couple of small powers on the map who would have had to both coordinate their units to stop the solo and prevent themselves from being taken out once a line was held. I didn't look through and see to what extent this was really possible -- it's not always possible of course -- but the bottom line is that you only get a solo when your opponents decide to let you have it, so you always want to be thinking about how to create conditions where you make it as easy as possible for them to make that decision.