From Nathii's list, yes, there are more southAmerican tournaments to disappear (also Moroccan) but it's also the period when there are most southAmerican challengers together with the end of the year, the rest of the year will be more in Europe and the USA, we'll see the situation there.
i think singapore and kazan are missing because these 2 cities hope they will be running wta championships
florianopolis is also getting ready for a wta tournament
nevertheless, it's still alarming
and latso, futures number also goes down this year for the record. anyway if all these "young players" were to travel from one 10K event to other 10K event for 4 yrs until they're ripe enough, they'd go bankrupt in no time
ofc challenger tour is needed, i don't know why people even question it. and it's prob also a thing of marketing, yes. in poland - szczecin, sopot, poznan, you wouldn't find a free place during the finals, many hundreds people watching them live