In response...
While I agree with the facts you've laid out in what will ultimately give LEO value, I disagree with the whole "only vote for people adding value to Leo" bit. I would argue that even though those people are siphoning off some of that value to other places, they are still adding "value" to the platform in other ways. Intangible ways.
First, most of them are still eyeballs on the platform, regardless of whether they are using other front-ends, thus MAUs. That factors into the ad revenue you're talking about. The more people using the platform, the higher the ads can sell for, the more revenue generated.
Second, while they may not be adding value now, if and when LEO starts moving back up, there's a good chance some of them will become people who add value with content later. These are basically the "warmest leads" you can find. They're people who already know the platform, have obviously already jumped through the onboarding hoops, and have taken the time to become at least somewhat familiar with Hive and it's communities. I would think it would be easier and more likely to convert them to the kind of contributors you're asking for than to find new ones from the masses.
Third, each of these people have a network of people they know and interact with. You never know when they will introduce new people to the platform that will become fantastic contributors. It's still a numbers game. We need users, be they strong or weak.
Lastly, it's got to be fun. It's all well and good to want to do things the way that makes the most sense for building the platform, but if everyone is worried about "Is this good content?" and "Should I be posting this?" you are taking away a lot of the fun. Being active and engaged is the name of the game in my book. I'm not necessarily worried about the content or where it originates. If we build a fun, engaging, vibrant community, I believe the financial part will take care of itself. Enough people will figure it out that we can all grow as a whole without cutting people out who aren't necessarily doing things with the best interests of Leo at heart.
There are always going to be people that are knowingly sucking off the system. No system is perfect or could ever get rid of that all. But this type of content still adds variety and character to the platform as a whole and I would argue is an important part of the overall experience. People that are just learning and getting started need to know that they can still participate, even if they're not necessarily doing things "right". There's a learning process. Some of them will figure it out and some won't. Voting is part of that process.
I would also argue that while you may be (intentionally or unintentionally) supporting content or authors that don't have the best interests of Leo as a whole at heart, you are still supporting the platform because half of your vote comes back to you, a supportive curator and member of the community. It doesn't all get siphoned off somewhere else.
So, in conclusion (since this turned into a post of it's own), while I believe everything you stated above is factually correct and should definitely be considered when curating and posting, I don't believe it's a "waste" if people are curating and voting on things that don't necessarily advance the platform in and of themselves. There are many intangibles that go into making a community a thriving and vibrant place---some good, some bad---but I would argue that all are necessary to growing as a whole. And while our curation behavior can certainly be improved upon by seeking to reward those who are contributing to the success of Leo, it should never be limited by that constraint. The last thing I want to see is an echo-chamber of like-minded individuals all telling each other how good they are. We've got plenty of that in the real-world right now and you can see how that's going.
Apparently I had a lot to say. lol
Good write and lots to think about.
Hive is the Way.