to all on this thread,
It seems as though you might be correct in this assumption, however the last time I expanded my city was on October 20th just 12 days ago. Yes the items needed for city expansion are at a minimum but as I had mentioned in another post "global trade center broken" I was able to purchase five or six of those items at the GTHQ in one night and others in another day/night.
Don't just look for the Dozer Blades, Stacks, Wheels, Security Cameras, Grates and Locks. Go to cities that "look like they have been just started" that have items released in early levels - for these expansion items but look in a market for an item that you do not need. You may be surprised at what you may find by looking for the wrong item as - it goes without saying the advertised item a lot of times is not the only item for sale. So dig deep, look in the non-obvious markets and look in the wrong place.
Having said that: is there a problem that has crept up in the last 12 days? I wouldn't think so because I have expanded my city storage in one of my cities twice in the last three weeks, to 220 and once in the other city to 220. At this level of storage you need 18+18+18 items to expand but I still manage.
I "read" on one of these threads back in the late winter of this year, February/March that one player theorized this game has "filters". I suppose he meant if you are looking for a certain item; the game call figure that out and then deny you the chance at obtaining them. Well ever since then I once in a while sell off the items I am looking for just in case there are filters in place. This is turn would fool the filters because the game then thinks you do not need them and viola the game starts giving them back to you. Is this a silly notion, is this true of this game? Don't know that for sure but it seems to work.
And last but not least I do concentrate on one expansion area at one time. Meaning I looking to expand city storage and nothing else or the beach area and nothing else or city expansion and nothing else. Will this work for you, maybe, its been successful for me and you do not use up all of you cities storage with expansion items leaving that space open for items needed to upgrade your buildings.
nw8240bp