Why do captains or spinners in the modern game tend to bowl with a deep point.

When I bowling there were many times, I beat the batsman in flight and bounce they were caught at point driving or cutting. I always thought the deep point was setting a field for bad bowling.

Why have things changed?

Totally agree.
The ring field seems to have disappeared. Deep point, deep mid on or off. So many easy singles these days. Why not force the batter to hit over the top, or against the spin through point
Playing in England with a number of quality offies, they taught me the 3 - 6 field. Only point, cover, and mid-off. Leg side - shortish backward square, silly mid-on, deep square, deep cow, catching mid wicket, mid-off saving one. Bowl outside off, spinning into the stumps.
Worked for the offies I played with.