How is modern One-day cricket different from what was played in its early days?

How is modern One-day cricket different from what was played in its early days?
When One-day cricket came into being, the English brought some interesting conventions also along with it! Here are some of them,

1. Bowlers had to concentrate on not allowing the batsmen to take runs, rather than getting wickets.
2. The scoring ate had to increase gradually from an initial low. In other words, it had to have the momentum of a car moving up from the first, to the top gear.
3. Spin bowlers are not to be included in one day cricket.
4. The team should not have batsmen who strike the ball very high. Batsmen who strike high in the first 25 overs also have no place in the team.

But batsmen who hit left and right, in and out of the ground are the rage of today’s One-day matches. Spinners have also become a crucial part of such matches. The modern style is to score as many runs as possible even in the first 15 overs which are subject to fielding regulations.