Of course it has. They aren't lunatics. They've sometimes spent despite having plenty but like any club refrained on other occasions.
They have not refrained. The key signings since 2007 is below. Look at the list and tell me how many of them were actually needed ?
They don't care about talents they have in their ranks . No matter how the existing players perform, when a new shining toy is available they always buy them.
2007/08
Signed Heinze despite having Marcelo in books.
Signed Saviola and Higuain despite having Raul, Ruud,Robinho
2008/09
Signed Huntelaar, VDV despite having Sneijder and other forwards mentioned above.
2009/10
Signed Alonso,Benzema,Kaka,CR7 despite having array of attacking talents already there.
2010/11
Adebayor,Ozil,Carvalho,ADM,Khedira when they had some exciting talents in their academy.
2011/12.
Coentrao,Sahin,Varane
2012/13
Diego Lopez,Essien,Modric,
2013/2014
Bale,Casemiro,Isco,Jese,Carvajal
2014/15
Hernandez,Navas,Kroos,James,
2015/16
Casilla(A GK again) Kovacic, Danilo, Vazquez
2016/17
Diaz,Llorente,Moratta
2017/18
Cabellos,Hakimi,Hernandez
2018/19
Diaz, Vicious, Odriozola,Courtois
In short, their transfer strategy is indeed lunatic.