How does one end the game when dominating the early and mid game?

So yesterday I played 2 games. The first game I was playing earth spirit pos4, and we completely dominated the enemy carry, while all our other lanes were doing fine too.

The other game I was playing Beastmaster mid, and completely dominated the enemy OD while our safelane was fine but offlane was doing meh.

Anyway, by the 20-30 minute mark we were at the enemies base constantly. They bunkered for a 10, 15 minutes but we just can't seem to break through.

We got rosh, but as it is in pubs, people were scattered for a short time, and single teammates overextended or got picked off. I am certainly at fault there too - I had aegis and thought getting their T3 tower bot + potential racks was better than getting their T2 mid. My team thought otherwise, one thing led to another I got charged by SB and dueled by legion, as I was alone bot lane.

Though we still pretty much never let them get past their T2 towers.

So what does one do in these situations where going high ground seems impossible, especially in a uncoordinated pub.

Most of the time the way these games end is by us throwing ourselves at them one too many times and they completely steamroll us within minutes, taking our ancient. Or we let them breathe just a little, get 2 pickoffs around the river and then go high ground.