perhaps I'm underestimating the space allocations for future guest races?
20 expansions will get you though guest races 8-14, far less if you ignore the quests and use portal profits.
I come across references to players having too many workshops, manufactories, and armories
Let's break this down a little
Too many workshops:
1. The wholesaler gives very low returns so if you are consistently dumping excess supplies there to buy goods, you'd be better off selling a workshop and building another factory to make the goods directly.
2. Many players think that they "don't have room" to place the Endless Excavation, Tome of Secrets, and Prosperity Towers. This is because they don't understand that in almost every case* these wonders
at level 1 actually produce more supplies per square than workshops since they don't require any culture or pop.
3. I suspect that very few players use as many PoP spells as they could sustainably use. Yes, a stockpile of spells is useful for the dragon abbey wonder, and or perhaps for disenchanting, but there are plenty of players(inc myself) who have 1,000+ PoP spells in the bank and don't use any PoP despite getting 10-30 every week from the tournament. A workshop with a PoP has the production of 3 workshops but only has the pop&culture costs of 1. I think PoP are very underutilized and many players would be better off (efficiency-wise) using a few each week and dropping a workshop)
Too many factories:
1. If a player has non-boosted factories they could replace those with boosted and end up with fewer total factories with higher total production. This does require trading partners though.
2. There is a point where a player can use so much space for factories that they can no longer fit many chapter buildings into their city. These players are generally producing far more goods than needed to progress through the tech tree, but wish to maintain ranking and tournament ability both of which would decrease by allocating more room for guest race buildings.
Too many Armories:
The main purpose of armories is to allow you more time between log-ins before your barracks completes training and sits idle. Orc production is usually a secondary concern and square for square craftable orc nests are better at it.
Really it is impossible to know if another player has too many unless you know how often they log in. Personally, I like to maintain a 12h training queue so I use this handy little calculator to figure out what combination of armories, SSS and DB wonders I need to maintain it. www.tinyurl/trainingcalc
*special cases:
The ToS isn't better than a worshop if your scout times are much longer than 2 days(unless you levelled the ToS)
The PT isn't better than a workshop if you only collect from it once a day
The EE isnt' better than a workshop if you make 1h bread 24 hours a day
None of them are better than a workshop with a PoP active