Sure you can scrape with no proxies, just use the detailed harvester and set a massive delay. I mean you might not like the speed, but its possible.
Proxies just are about speed is all, the more you have the faster you can go.
So maybe you need a 5 minute or 10 minute delay on detailed harvester. Maybe thats fine for you while you sleep and you don't need a lot of results, go for it. Maybe its too slow for production and you need proxies, its just about time.
you can start high on the delay and then keep lowering it till you start getting blocked and then you kind of know the sweet spot for that query type.