Not trying to dispute the point that "players with similar or better profiles than Henderson went for much less" and why we weren't in the race to sign these players is probably another topic of its own but its worth noting the situation most cases were in:
- Isco joined Malaga from Valencia's B team as a 19 year old (
having played only 200 mins of top flight football)
- Cabaye's cost was apparently due to the
activation of a release clause
- Vidal had
a year left on his contract
- Şahin had a
release clause in his contract
- Gundogan had
a year left on his contract
- When Herrera was sold, Real Zaragoza was
in debt and filed for bankruptcy that year
- Pjanic was sold in 2011 (Toulalan too) but Lyon still
posted a net loss of €28 million and needed further sales
whereas Henderson featured 37 times in a Sunderland side that finished 10th in the league, signed a new contract at the start of that season and was Sunderland's Young Player of the Year for 2 consecutive seasons.
With the exception of Newcastle, the clubs these players joined were pretty much on the up.
Juve splashed €145m, Roma nett spent almost €60m after the American takeover. Dortmund were the defending Bundesliga champions and Malaga went on spending spree (Cazorla, Joaquin, Toulalan etc.) after takeover.