Abandonware is not legal, so no support for something like that?

If Abandonware isn't legal, so why not have a partenership with a legal equivalent.

But why do this at all?

for easy access to old games for people not able to use dos

Too much trouble securing distribution rights.

Use GOG.

You know, GOG is pretty much that thing already, except its not "integrated" into dosbox, and many digital download of old dosgames you buy on paysite use an integrated dosbox. Personally i like my Dosbox solid, simple and standalone, just as it is already without any crapware in it.

Actually games dos games from gog come with dosbox if I'm not mistaken

And if you want to "be able to select a game by simply clicking on an icon", just use one of the front-ends.