This is not true unless you craft very little or have a boneyard(past or present). Given your years of play and linked cities is perfectly understandable that you have excess spell fragments and a diamond hoard.
Most players dont have your surplus of diamonds and many players craft often to open the mystical object for the chance at diamonds. Boneyards are a legacy build so new players do not have and will not be able to get excessive spell fragments unless they reduce crafting.
Dad & I only have a 'sizable pile of diamonds' because there's been nothing actually worth spending the damn things on!
More expansions? Sure, if we want to make our tournies + spire harder...
Magic buildings? Especially for dad, after nearly 2 years of the spire, he has more magic buildings than he can place!
Events? Why bother when the prizes have been mostly hot garbage for so long?
The only thing we spend dias on is an extra turn for negotiating in the spire, and we win back far more than we spend every week, hence why we have so many of them.
It doesn't take that long to build up a sizable pile of junk, just find a good fellowship that isn't full of noob-hating elitists.
The only real hurdle is to get ALL those annoying evo buildings out of the crafting rotation since those *do* eat up a metric gak ton of CC's & frags to craft. (...and more annoyingly, will make it near impossible to ever get even a single UUU/ELR/MMM to show up!)
Once you establish yourself in a decent fellowship that can hit 10 chests every week, (which isn't hard anymore), and gain the Lv2 fellowship rewards from the Spire every week, you will have more than sufficient resources to maintain everything.
Does it happen over night? Of course not!
Is it possible to achieve within 6-10 months? Absolutely.