This is completely false, what's your source? Also, it has never been the case. I recall that at some point around 2015, about 4/9 persons with commit access to the github repository (please note that this is a far fetched attempt to find out a metric for "controlled") were co-founders or employees at Blockstream, but right now I am not sure there are more than four or five, out of ~30.

Sources:

https://github.com/orgs/bitcoin/people

https://bitcoin.stackexchange.com/questions/35907/bitcoin-no...