Shaw has had 4yrs to prove himself and under different managers has failed to impress.
Why would you want to give such a player a chance. It makes no sense.
Shaw has no ambition and is doing the bare minimum. This is not the kind of player who does well at any top club.
Southampton is his correct level - ie. a club near the bottom of the league.
You are referring to a different era. Since we brought through those youngsters, all at the same time, it's been decades and no team has ever been able to recreate that sort of scenario (ie. bring through youngsters who form the core of your team, who go onto win everything). Leeds tried it way back when, bringing in youngsters and playing them in their first team. They did well, but ultimately, it all went pear shaped for them.
If we were reigning league champs, cruising to titles, in the 90s, sure, we could try using youngsters, but in 2018, if you make heavy use of youngsters, eventually they'll get torn to shreds. Did you not watch the Ajax vs MUFC EL Final? Those youngsters stood no chance. It was literally men against boys.