I think there might be a few problems with this...
For example, monitoring "viewing-time" is something that is simply not possible on this platform... unlike facebook, instagram, twitter etc, there can be thousands of interfaces to access the steem blockchain and there is no guarantee that each will implement the right way of monitoring "view-time". I don't think that is technically possible.
And... I am not going to comment either on the author/curator payout debate or self-voting-practice debate...
As I said, this is not likely to happen on Steem, some reasons for that are mentioned in your comment. But a new SMT could very well adopt a one-interface policy where this can be measured.
I would even go further with this. Maybe that SMT could collect voting patterns and reduce payouts when the same accounts always vote exactly the same. That would make multiple accounts, acting together for maximum payout a strategy that doesn't pay.
Ultimately I think that the behavior you will get on a platform is determined by the way you set up the parameters when there's money in play. If bad behavior leads to monetary rewards, that's what you will see. You simply cannot expect all humanity to adhere to decency standards.