There are egregious cases in history (e.g., Rosalind Franklin) but nowadays most of modern research is conducted as a group so it's logistically hard to award it to anyone other than the principal investigators of the lab.

It's a bit sad that the original purpose of the prize is lost but that just reflects that we're past the age of lone genius contributors making a difference. No one person really matters. You can replace that grad student or PI with another and the machine will still chug along.