Simply put, Jack Nicklaus said that he could carry about 260 swinging as hard as he could. He rarely hit over 300 unless he has a tailwind, downhill, and dry fairways. I'd say the same for pros nowadays. They don't carry 300 yards unless they're going downhill, downwind and on dry fairways. Most of them carry about 230 (estimate) and it rolls about 50 yards. These courses that the pros play on are dried out hard and fast. No wonder they hit it so far! Also these courses have a lot of wind. If they have a headwind, they merely hit it lower. If they have a tailwind, look out there's going to be some bombs, especially if it's downhill and the fairways are hard. I hit my drives about 200 carry and if I had these conditions described here I could hit it 270 (maybe 250) No wonder it doesn't look like they're trying. They let the course take care of distance for them.
Also, Jack also said that a course he had a hand in designing called harbor town, there was a hole in which there was a creek separating two fairways and he said that it carried about 230. But he also said that he couldn't carry that spot unless he hit his absolutely best shot. He said that if he hit it even just a bit thin, he wouldn't be able to carry, no matter how hard he swung. This makes sense because most of us only drive about 230 on average, but we play on slow courses and we don't swing very hard. I swing all out and I still can't get it past 220 on the range, but on a fast course I can get it to 280. So generally, this is my opinion on how the pros hit it so far.
Another factor though, is how strong these guys are; they swing so fast because of their strength. So if you want more distance, work out. Simple as that.
That's my opinion.
Sources: Jack Nicklaus' Book Golf My Way and my own logic
Comment freely. Thank you for your concern, and I appreciate your responses
Have a nice rest of your week,