they don't need to do this and likely don't care to. web ui exists. microsoft doesn't even care about native anymore. they are focusing on .net maui cross platform/web (with blazor) stuff and AI.
the days of snappy portable applications are over. unless you want to stick with win32. and nothing wrong with that. in win32, you have the tools to create any look and feel you want. the author just doesn't care put in the time to do that and wants something pre-built while conforming to his demands.
lazarus is great, but the GUI library it comes with has the same issues that the author is concerned about... try changing the theme colors to a dark theme... you end up with something looking like crap with all the other controls using standard colors.
the days of snappy portable applications are over. unless you want to stick with win32. and nothing wrong with that. in win32, you have the tools to create any look and feel you want. the author just doesn't care put in the time to do that and wants something pre-built while conforming to his demands.