Indeed. My guess is you see the liberty wins mostly in the mid month low difficulty games. They are most likely to be the short games and if they are not, they are the ones where you might have the chance to expand enough for liberty to be good. 7 cities is increasingly rare as you go up in difficulty level.
What I have seen and experienced has been that liberty is fantastic for getting every good city you want out and planted before anyone else can claim those spots. It stinks from turn 70-200, but if you treat those 7-10 cities like you would a nice 4 cities tradition empire (Which only the best can pull off properly) and work proper tiles, fill out other social policies, get lots of farms, and do what you can to make up for the lack of 15% growth, happiness problems, etc. etc. etc. then from turn 200 on up the larger, properly built empire will surpass the smaller, properly built empire. That last part is a giant gamble, but the first part (Pre-turn 70) is where liberty really shines.
No other policy offers a free settler and then double-speed settlers. You can literally build twice as many settlers after you take collective rule as a tradition player. Their best policies don't kick in until turn 50 on standard when you take Monarchy, Landed Elite, and the amazing finisher. Free monuments are nice, but not nearly as good as 2 free food plus 10% growth, or half unhappiness in capital, or 15% growth and free aqueducts. Oligarchy and aristocracy really suck, on so many levels, I don't think anyone can really defend those policies. Regarding the good policies, they need time to move to get you the buffs you need. So its not until around turn 70ish when things start really moving with tradition.
Liberty dies off here, because 1 happiness per city connection sucks and 33% less policy cost just evens things out. 1 hammer per city also sucks, the only thing that lasts long term with liberty is the faster worker improvement, but that only helps if you build the pyramids. I personally think hanging gardens is a better wonder, 6 food that early is great (TOA is better long term, I think its placement on the tech tree stinks personally but it stacks wonderfully with tradition finisher if you can obtain it somehow). Anyways, the only way to recover is to play well until your skillfully placed cities can catch up to the faster growing tradition cities. 1 extra hammer per city looks good math-wise, but higher population means you can work more mines so that point is defeated when the map gets in the way. The map and the neighbors are the real deciding factor here, liberty doesn't work when you only have room for 2 cities.
With Liberty, you have to start building settlers right before you get collective rule and send them right up in your neighbor's face. Then back-fill the spots with later settlers that are in between the first cities and the new ones. Once that is done, focus on defense, happiness, and growth. It takes more skill, because the AI is peeved you forward-settled them and will send armies of death to take your land. Build walls, build crossbows, and enjoy the show. Happiness is always my biggest problem, I can never get the jerks to trade me enough luxuries even AFTER I build coliseums. Once ideologies kick in, happiness explodes but its a painful uphill battle from turn 70-200. Its easy to defend 4 cities, and the AI could care less about your pitiful empire even with a 0 defense score. Defending 8 is a challenge, but if those 8 can survive, they can grow as tall or taller than many 4 city tradition empires and victory comes quicker (Supposedly). It's so difficult to determine which is faster though because each game is so different.
