I'm not trying to say it can't be done. I'm just nowhere near as confident as you are about the lack of downstream impacts.
Historically, there have been several hiccups (at least on the Steemit front) where significantly increased activity on the Steem blockchain has disrupted the "face of Steem" (also referred to as the Steemit website).
Simply because the Steem Blockchain is functioning as planned, doesn't change the fact that the majority of Steem in circulation exists on Steemit. If Steemit is disrupted, Steem therefore becomes less valuable.
At least until SMTs come out and become more profitable than Steemit and people cash in their stake...
Sorry, but this is not how it works. The STEEM that you see in your Steemit.com wallet, is actually in your Steem blockchain wallet. The website just shows you the tokens that exist in your blockchain account. You could use any other Steem wallet interface (example Vessel) and you would see the same tokens there.
Yeah this is so inaccurate it's "not even wrong." It doesn't even make sense.
While that may not be "how it works", I would be willing to state, with a large probability of accuracy, that 80% or more of current, active, Steemit users do NOT use any other interface for their Steem Wallet outside from Steemit.
The performance issues have been addressed, and the dev team continues to work on more improvements. There are multiple wallets available as a work around if there ever is an issue. I don’t think there is as big of a problem as you think there is.
I'm not saying that there is a problem currently. I'm just saying that history has proven that when significantly increased load has been added on the Steem blockchain, the Steemit page has suffered.
That is all.
Again, I haven't said that I don't think it will work. I agree that the Steem blockchain will survive. I am, however, skeptical about the level of success and speed of recovery from any potential issues that may arise from such a significant increase in transactions.
Side-question, along the same lines as the context of your post here ... Is it possible to "Power Down" from these other wallets? Or the future mobile wallet that @andrarchy mentioned above?
Yes, of course it is. The steemit website is just an interface to the blockchain - you can use any other interface to interact with it to perform any functions, including wallet based ones.
I understand the concept of Steemit being connected to the Blockchain of Steem. I also understand how the back-end data is stored, at least from the SteemSQL side.
Where I fall short is with the various apps, because I (along with the majority of other non-developers) have no incentive to use additional APIs to connect to the Steem Blockchain outside of the Steemit webpage.
If Steemit failed, I would research and try to become more savvy with such an endeavor, however as there is no current need (or a foreseeable future need), I have not invested my time with researching alternatives to what is already woking. With that said, you have physically used and accessed a wallet other than on Steemit's webpage, which includes Power Down functionality?
P.S. I liked your video on how to code a Steem app for posting content within 9 minutes.
Here are just a few of the other services that are available to connect to the blockchain:
https://github.com/aaroncox/vessel/ (desktop wallet)
https://busy.org/ (alternate front-end site, like steemit.com)
https://chainbb.com/ (another different front-end)
https://esteem.ws/ (another front-end)
Hope this helps :)