I don’t think there are any sustainable fully open source software out there that are used for consumers besides the ones that reach a critical mass of support. And even then as a software gets more complex the more there are sacrifices to the FOSS model. You should read the boad discuss forum for TDF/Libreoffice. Collabora is trying to nerf the free version of TDF and the board reps are in this toxic battle with Collabora board reps. Eventually FOSS software needs a stable revenue stream besides donations.