Partly because even 'cheap' players back in 2013 would be going for at least £30m in today's market.We have a history of buying cheap players and turning them into class. Why do we want to get away from a winning formula?
Eriksen was the jewel in the crown at Ajax with a year left on his contract (so timing-wise we were fortunate) but going for an equivalent like Sanchez last year ended up being our record transfer fee.