Well the issue here is, sustainability simply means that the product continues to exist. As more and more people are finding and using it I don’t think we can say it is unsustainable. It is unclear as to whether a paid project would be sustainable because that would require a certain amount of consistent funding over a long period of time. If we were to go forward with creating an OpenCollective it is unclear where the donations to fund it would come from as LibreTime is a niche product and it is primarily used by broadcasters with limited budgets.
I appreciate the enthusiasm but I don’t think @hairmare has much available time as he already I believe has a full-time job and my ability to focus on the project is rather limited as well for the immediate future.
So without dismissing this entirely I think that we should test the water so to speak and without coming up with a grand plan to build a paid development team a next step would be to setup a process for taking donations and distributing them to developers who are contributing and can use the funds. OpenCollective could be a way to pursue this. I also have a 501c3 non-profit I am involved in that could help facilitate some of this.