Purism is currently only paying 7 developers to work on the Librem 5's software, yet they are managing to create a viable mobile system, which is a good indication that Phosh using an existing desktop stack (GTK/GNOME) is the right strategy for producing mobile Linux with the least amount of work. Given that it can easily be included in every desktop distro, it is also the right strategy for getting adopted by all the major distros.
KDE Plasma Mobile is the second best strategy, in my opinion, but it has to worry about maintenance of its mobile stack, and it has a lot of separate mobile apps to maintain, and it will be harder to convince the major distros to adopt it.
I honestly don't think that Ubuntu Touch and Lomiri are viable options in the long term, due to the lack of code commits over the last 3 years. UBports is going to have to attract a lot of new committed volunteers to maintain their codebase, and I'm skeptical that it will happen. UBports has the right strategy in trying to get its packages into Debian and trying to create an active community, but it is going to be an uphill battle.
If you are volunteer programmer that wants to spend 10 hours per week working on mobile Linux, I think that it is far more likely that you will chose Plasma Mobile if you are a Qt programmer or Phosh if you are a GTK programmer, rather than UBports. Volunteers programmers will look all that unmaintained code and see desktop distros adopting Phosh and Plasma Mobile and decide to put their time into a system that looks like it will become successful. KDE and GNOME already have hundreds of programmers that contribute to the projects, so it is a natural extension for those same programmers to extend their work to mobile, but jumping into the Ubuntu Touch and Lomiri codebase which is siloed code is a much less attractive option for volunteer programmers.
Maybe I will be proven wrong, but my prediction is that KDE Plasma Mobile is guaranteed to be a long-term success, because it already has enough volunteers to always maintain it. Phosh is less certain, because at this point it still depends on Purism, whose finances are shaky. However, if Purism can get Phosh to a good enough state, it is going to become the default mobile interface for most of the current users of GTK/GNOME software because most desktop distros are going to adopt it, and every maintainer of GTK/GNOME software will have a very strong incentive to work on incorporating libhandy, especially once it becomes part of GTK 4.
As new companies jump into the mobile Linux market in the future, I bet that they will chose either Plasma Mobile or Phosh, because they will look at the number of code commits for UBports, LuneOS, Nemo Mobile, and Maemo Leste and decide that they aren't being well maintained, and they won't want to deal with the proprietary bits in Tizen and licensing fees for Sailfish OS.
KDE Plasma Mobile is the second best strategy, in my opinion, but it has to worry about maintenance of its mobile stack, and it has a lot of separate mobile apps to maintain, and it will be harder to convince the major distros to adopt it.
I honestly don't think that Ubuntu Touch and Lomiri are viable options in the long term, due to the lack of code commits over the last 3 years. UBports is going to have to attract a lot of new committed volunteers to maintain their codebase, and I'm skeptical that it will happen. UBports has the right strategy in trying to get its packages into Debian and trying to create an active community, but it is going to be an uphill battle.
If you are volunteer programmer that wants to spend 10 hours per week working on mobile Linux, I think that it is far more likely that you will chose Plasma Mobile if you are a Qt programmer or Phosh if you are a GTK programmer, rather than UBports. Volunteers programmers will look all that unmaintained code and see desktop distros adopting Phosh and Plasma Mobile and decide to put their time into a system that looks like it will become successful. KDE and GNOME already have hundreds of programmers that contribute to the projects, so it is a natural extension for those same programmers to extend their work to mobile, but jumping into the Ubuntu Touch and Lomiri codebase which is siloed code is a much less attractive option for volunteer programmers.
Maybe I will be proven wrong, but my prediction is that KDE Plasma Mobile is guaranteed to be a long-term success, because it already has enough volunteers to always maintain it. Phosh is less certain, because at this point it still depends on Purism, whose finances are shaky. However, if Purism can get Phosh to a good enough state, it is going to become the default mobile interface for most of the current users of GTK/GNOME software because most desktop distros are going to adopt it, and every maintainer of GTK/GNOME software will have a very strong incentive to work on incorporating libhandy, especially once it becomes part of GTK 4.
As new companies jump into the mobile Linux market in the future, I bet that they will chose either Plasma Mobile or Phosh, because they will look at the number of code commits for UBports, LuneOS, Nemo Mobile, and Maemo Leste and decide that they aren't being well maintained, and they won't want to deal with the proprietary bits in Tizen and licensing fees for Sailfish OS.