you are not wrong on the comparison but you miss the tools available to contain a desktop application that are not available for a browser application. by default a browser application is more limited than a desktop application, but those limitations also reduce the possible functionality of a browser application, and they are locked in place as far as i am aware of.
for a desktop application, at least on linux there are tools available to further constrain its access to the system by monitoring its activity, removing capabilities or placing the app in a container or even a VM. (VM are available on windows and mac too, but i don't know about other features)
to contain a browser app in this way i would have to run a contained copy of the browser as a whole, and i still can't easily limit network access.
further, almost all desktop applications on linux come from a trusted source or a trusted intermediary and have undergone at least some kind of review, whereas browser applications can be reviewed but it is non-trivial to ascertain that i am running the exact same version that was reviewed.
it is possible, and it is my hope for all this to change. i actually believe browser applications are a good idea, but the ability to audit, and constrain browser applications needs to improve a lot for that to happen.
for a desktop application, at least on linux there are tools available to further constrain its access to the system by monitoring its activity, removing capabilities or placing the app in a container or even a VM. (VM are available on windows and mac too, but i don't know about other features)
to contain a browser app in this way i would have to run a contained copy of the browser as a whole, and i still can't easily limit network access.
further, almost all desktop applications on linux come from a trusted source or a trusted intermediary and have undergone at least some kind of review, whereas browser applications can be reviewed but it is non-trivial to ascertain that i am running the exact same version that was reviewed.
it is possible, and it is my hope for all this to change. i actually believe browser applications are a good idea, but the ability to audit, and constrain browser applications needs to improve a lot for that to happen.