This is no speculation. Back in the late 90s I had a list of the congregations of the state I was from. There were 350 congregations in 230 Kingdom Halls.
I compared that list to what is currently listed on Jw.org.
There have been about 36 congregation and KH deleted.
4 congregations deleted from multiples congs per KH.
One city had 3 congs in one KH and 2 in another now there is 4 in one KH.
There are 4 congregations that remained in intact but they sold their KH and are going to a more distant KH.
The major metropolitan city had roughly 23 Kingdom Halls then that don't exist now and 6 that exist now but not today. I can't guess exactly how the congregations were moved, or created or deleted with all that.
Some new congregations were created but they were foreign language.
Today I get 304 congregations in 169 KH total so a net loss of 50 congregations and 61 KH in the state over the past 20 years.