Look, when spending millions of pounds you have to be careful, even at the best of times it's a risk.
You don't just walk into the footballer store and buy the one you want off the shelf, Wenger will have be tracking certain players for months if not years so the chances of his prefered target falling into his lap at the right price at the right time is slight especially in January.
Thats why he prefers cheaper low risk options, sometimes you get a Park sometimes a Flamini but it's not a big deal if they fail, whereas if he splashes out now on another Jeffers.......