Let's break down the points made,
1st paragraph, the lower leagues are full of released players with various technical ability, from various top level clubs including saints. They've all been good enough to be in their respective youth systems.
2nd paragraph, you run about and close opposition down at EVERY level, at least you should or you'll be released. Not every team hoofs balls up to big target men, some do though, even at the top level.
3rd paragraph, and so you should, they're all trying to win places in the first team ultimately. There will be circumstances where better players are released due to having enough players in respective positions but that's a choice for the coaching staff to make, that's what they're paid for, And to be honest if you're good enough, taking a step back can be the making of you, see Stephen Dobbie.
Paragraph 4, Saints are striving to be the best they can be, you cannot slag the club for reaching Europe and cup finals and semis etc. If the youngsters are good enough and determined enough they will succeed, whether that's at Saints or elsewhere. Fans having unrealistic expectations isn't something new, you get that at the bottom level too.
I'll add that in the last few years Saints have given probably more chances than what certain young players have deserved. They simply weren't good enough and have rightly been shipped out. The ones who have reached 1st team level at the moment? The only one who maybe deserves more of a chance is Liam Gordon, he hasn't put a single foot wrong in the games he's played.