Ostensibly the parties are choosing select people through a strict vetting process. I think informing yourself about individuals would be much more difficult than picking a party with a long, presumably representative history.

There's also a considerable barrier to entry. Louis Rossmann had Larry Sharpe on, who had an interesting talking points in the first three minutes:

https://www.youtube.com/watch?v=HhqTxlxOQBM

I think the key point is that the media wouldn't cover him if he didn't buy ads, and the cost of a poll stood at $40,000. How far can you campaign on a shoestring budget? It's a little easier when you can pool resources through an institution or a party while also gaining the immense benefit of a much more robust network of connections.

Those are some of the infrastructural barriers we've got to overcome, and I can't imagine that movement in that direction would go uncontested. It's quite the uphill battle.