If that was to happen then when FBI breakdown the silk route and found the chunk of bitcoins in this process would not have been selling it in open market. Once more think that when they are selling this bitcoins means they are supporting it. So i think what OP is expecting is not possible. But still cannot say about future. If that happens then it will be benefit for the other Altcoins as Bitcoin will lose the faith from its investors and they will diverse themselves to other altcoin.
just holding coins does not mean controlling.
however spending the coins where the funds influence devs or bitcoin businesses to be swayed in a particular direction does create control.
by this 'sway business' i dont mean businesses change bitcoin code rules. but if a business was to only accept 'whitelisted' coins or was told to only accept litecoin.. then suddenly people will see less utility of using bitcoin if they cant spend it with certain businesses.
id say i have more coins than you as i have had a nice hoard since 2012. but i dont flash my stash, because i know my coin hoard has no meaningful control over anything.
thus id say my hoard has no more control than your hoard of coins..
however if i bounty campaigned or VC funded a dev team to change the rules.. then things would become controlled
take DCG.CO having ownership stake in blockstream that coded segwit. ownership stake in bloq that done segwitx2, ownership stake in blockchain.info(ver) that gave opposition the fake "free choice". ownership stake in many merchant/exchanges and payment gateways that formed the NYA agreement. ownership stake in a few other people (USAF)
you'll see that things did change and anyone else was just sheep herded into the change activation via the "compatibility" trick where by not upgrading didnt actually prevent activation. thus people in the general community could not vote/veto/prevent the change.
so yea FBI hoarding silkroad funds caused nothing. but spending coins means THEY now have more fiat. to buy more guns and swat raid bitcoin business or send out court orders to sway businesses into doing what the fbi/sec want
thats why we need to ensure we are not reliant on third parties. and not reliant on single team of devs. to avoid us falling into the trap of corruption and monopoly games