As ned stated (not mentioning him to avoid troubling him too much), those are only hypothetical tokens. They were invented just to show what SMT's would be capable of doing. If however they are added to Steemit, this wouldn't be bad for the Steem blockchain but just for Steemit ! Other Steem apps would have their own or no SMT's and those wouldn't have anything to do with the GPT's. What you are scared of is one of the reasons why SMT's will be so good in my opinion. Some websites don't want to be decentralized and want to be able to filter content (by quality, political view...), with SMT's they will be able to do so. This doesn't mean that all websites will do the same ! Ultimately the power will be in our hands as users to pick our platforms, it will be our fault if we decide to pick a centralized one. Content posted on the blockchain will still act the same as it does now (with trending, hot, created, vote weight...). Just think of SMT's as a layer added on top of the posts generated by a specific app to make it more convenient for the app to get what it needs (trending by vote count instead of post value for example).
That's what I think I've understood from everything that's been said about SMT's so far. Hopefully it's correct because that would be amazing !
thanks for your comments. lemme just clarify a few things.
the future you described is awesome. i'll love it, and certainly not be afraid of it.
but it will only come under certain conditions. that i'm very afraid.
you can't have websites competing each other like that when GPT is the only dominant SMT. yes you can have 1000s and 1000s of different dapps/websites/bots/etc on top of the steem blockchain, each having their own SMTs, but the sheer number is not an issue at all. it's whether an SMT can create a rewards pool or not.
GPT will do it. nobody doubts that. @ned even hinted that it could be used as a metric for quality posts. people will trade it. now you need someone who can match that rewards pool otherwise it's not a competition. it's gotta be someone who has enough followers and influence that his/her SMT will match the total marketcap (most tokens won't even have a marketcap). but nobody in this community is bigger than @ned.
it's why i keep saying you need a bigger player entering with a new SMT. it's the only way to ensure that steem will be an ecosystem for all sorts of SMTs. if not, GPT will be the dominant one. it's a token verified by steemit inc according to their own behavioral guidelines.