"Except that without the company, the rest just falls apart, it might still exist on servers, just minus everything that gives it value stripped away"
And that is exactly what blows my mind when I hear so many people naively talk about crypo and blockchains. Somehow they have adopted the false belief that if you have a decentralized system, it can continue on even if, and after, its founding company folds. Yet in reality, nothing could be further from the truth. As you so accurately pointed out, there is so much more to a successful coin or blockchain than its blockchain. Without the company behind it (providing core centralization), the rest is just a pile of unorganized parts which will very quickly fall apart on their own, and then everything is lost.
There was a bit of a mixup; In general cryptos can operate in a decentralized way, they aren't connected to anything like with Steem, where value is at least in part derived from interaction with the platform.
That could be a nitpicking distinction.
The reality of the way blockchains are operating now is far closer to the operation of a ponzi scheme than anything else (regardless of steem), consider, anyone could create a block chain. They convince others to invest, which gives the blockchain SOME value, and the increase in value only comes in from increasing people being convinced to invest so that they gain value in the coin from future investors. Whether that be investment of time, machinery or funding into the crypto 'markets'.