If by using term "experienced" you mean good defender who played in the premier league before than you're right - surely it is hard to get one on cheap.
But buying outside of the premier league you could get Skrtel (6mln), Lovren (8mln), vlaar (3mln), de vrij(8mln) the list goes on. Surely these are not world's greats but personallyi rate them all more than scott dann
Skrtel, unfortunately

, has turned out a decent buy but he was 6m in Jan 2008, prices have escalated a bit since then.
Lovren was a good buy at 8m for S'ton but hasn't really kicked on for Liverpool as you pointed out yourself - were his weaknesses covered by Fonte (who btw was a cracking signing for 1.2m in 2010)?
We have no idea how Stefan De Vrij would do in the premier league and at 8m he is the same price range anyway that we are disucussing.
Ron Vlaar I thought might go to Utd last summer in the transfer window, especially with the LVG connection. He has good leadership skills, is a solid defender and is versatile in the way he can play in back three as well as as back four. Bit of an iffy injury record but overall think he was an excellent signing for the price in 2012.
Overall not disagreeing with you that you can strike it lucky, just think it way, way harder than your initial posts suggested in the current market with every premier league team looking for the same thing and with money to spend.
Edit btw I didn't necessarily mean premier league experienced but we do need someone who not only knows how to manage his own game but potentially be able to step in and direct inexperiened youngsters - doubt you'd get that confidence without at least 3 years of first team football at a decent level.