Not misunderstanding you, just not agreeing with you. The issue with letting Sagna go is that there really aren't many if any right backs that are obtainable who are an improvement on him. Off the top of my head the only one who I feel would be comparable and possibly obtainable is Pisczek at Dortmund, he wouldn't come cheap though.
There are plenty of great younger developing talents like Coleman at Everton, Clyne at Southamption, in France there is a great young right back breaking through called Serge Aurier who plays for Toulouse. They won't come cheap though and can you really see Arsene paying the market rate for them?
Back onto Sagna, he basically wants paying the market rate for a top quality established international full back, I honestly don't think demands of 100k per week are excessive. As stated by MO, 100k per week is now the going rate for an established player, elite players command 150-300k per week.
Kim Kallstrom the best we could get in at the time? He's injured for christ sake! Arsene even admitted he was aware of his back problem but took a gamble!!!
You honestly think Bendtner is as good as Berbatov?! How have you come to this conclusion? Just curious.