You have in a single paragraph(and what a long paragraph!) argued very successfully for abandonment of following ideas at their conception itself:
1. Research in medical science(why bother saving the poor? It is all vanity in any case)
2. Research in aviation(Oh those damned Wright brothers! Trying to get all these poor masses to fly in air. It will have no practical application! Flight will be of no use to mankind... it is all vanity.)
3. All works of art and literature, cinema etc.. (Entertaining the masses ? Who wants these poor folks to be entertained ? They are a pox on us, I tell you! Wanting your name to live on, after you are dead ? Vanity! It is all vanity, I tell you!).
4. Research in navigation and seafaring.(Bah! Trying to get all those poor teeming masses to float on water and go to some place farway. Discovering new searoutes and lands ? What for? Who cares about whether these damned undeserving poor folks go to this place called the New World and establish some country called America... or populate some place called Australia. America...bah! who needs it!)
Get a clue. You might be actually be right about things being done for sake of vanity. And yet the results are usually of great benefit to mankind, that seem inconceivable at worst, and farfetched at best.
If your forefathers had thought like you, there would be no America or Australia. And you wouldn't be here preaching to us about vanity and questioning the rights of those less fortunate than you, to exist.