I agree with @steve and think he gets to the heart of the matter ----->50k nodes is a surplus and the marketplace will eat into that surplus if the economics continue to become unprofitable.
I also agree with @adam that encouraging applications to stake gets to the heart of the model —> completing the economic flywheel is the cleanest solution we all want.
Re: nodes becoming unprofitable - We should remind ourselves that it is a permissionless protocol and that no one at Pocket Network prescribed 50k nodes. Node count went from 15k to 50k YTD because that is where the market was heading.
The permissionless part goes both ways too. Several thousand nodes may unstake and that is marketplace feedback. Yes, those unstaked POKT will be supply-side sell pressure, but it is part of the marketplace feedback.
Those who stick around will innovate, compete, and endure different cost structures. They will weather ensuing price action will benefit from more rewards. They will also benefit from demand-side buy pressure as new sinks (portal monetization, Application Burn Rate, etc) come online.
Re: Encouraging Applications to stake -
Any robust solution should be focused on this as the centerpiece. I see innovation in creating new portals, DAO-led buy backs, or different payment structures as the key to the economic flywheel.
This is why this forum post is special - it outlines ways (and alpha) in how we can all contribute to application burn rate. It may take a while for the protocol team to design, code, test, and implement this into the core product. In the interim, all proposals to start introducing app-based sinks will get a serious look.
Full disclaimer - I am not 100% there yet with the options of a weighted staked, increasing the minimum stake, or a buy back, although I see pros in all options. I am keen to support a supply-side solution, but (based on my commentary above) am inclined to more market or demand-side solutions.