Actually, the better question is: When will they replace most desktop Linux programs?
Sandboxing is a buzzword here. Look at the flatpaks, people don’t sandbox, they apply the maximum permissions until the application stops making errors at startup. This is not sandboxing.
And don’t expect for a second that the security will be enforced on older libraries.
people don’t sandbox
Yes they do. Do they all sandbox all things? No. Does it require sandboxing? No. But these are moot points. If you need it, you can have it. These are not available with traditional packages. Whether or not something works properly when sandboxed is sort of a side point, because it simply means that stuff needs to be worked-out. Since when do we have perfect stuff out of the box in FOSS though?
You’re holding it to greater standards, IMO.