In all honesty, there's no way to know if any particular group has control except when they clearly assert it. This was done previously, but I think is less so since many prominent Blockstream employed went on to other projects. Now we (or most of all of course those invested in ticker BTC) are instead dealing with the remnants.
You can blame high fees on "attackers" all you like, but the Bitcoin design (now in use by BCH) doesn't take motivations into account to this degree, nor should it have to or does it change the fundamentals of the network itself.