Being able to taste bitterness is just the starting point, you can learn to like it. Few people really enjoy their first real beer (as in one with hop bitterness, not the faux lagers youngsters prefer) but quickly learn to like it. Same thing happens with vegetables, though obviously plenty of folk never gain mature tastes.
Personally I'm worried about this mention of 'sweet', does the world really need another dumbed down food with it's distinctive flavours stripped back to what lazy, immature tastes can cope with? That's how we got flavourless tomatoes, lettuce with no hint of bitterness or other actual flavour, apples that taste like water and sweet sprouts. I like my food pleasantly challenging, not turned into tasteless mush.