What was the Reason Why Reserves was replaced with U23s ?

I'm not sure why Reserve teams was replaced by u23s but its not working , when I was a youngster yrs ago , the reserves always seemed to get a good crowd watching and it gave first team players back from injury game time ,

or players that have been off form game time ,

I'm not sure why Reserve teams was replaced by u23s but its not working , when I was a youngster yrs ago , the reserves always seemed to get a good crowd watching and it gave first team players back from injury game time ,

or players that have been off form game time ,

Remember when I was a kid in the early 60s and bought the green in,if they wasn't at home would look for the Sheffield Wednesday R result,they always played Saturdays too.