We can definitely sign someone, so I'm not sure how you've come to that conclusion. According the Kieran Maguire we could buy a £30m player 'without it touching the sides' in terms of PSR. The issue is the so called 'Newcastle Tax' and the outdated PSR restrictions. If they were up to date, we could spend more. The Newcastle Tax refers to us being; a PL club, with a reputation for being the richest club in the world, who're currently decimated with injuries. Big clubs don't want to help out a threat to the status quo, chasing pack don't want to help a team they're in direct competition with and the rest don't want to help out a team who's currently vulnerable. Which I get and don't have a problem with.
So we should have thrown games to avoid the Champions League, or failed to strengthen in this summer after achieving CL football for the first time in 20yrs?
Had we progressed from the group stage (which we were 30 minutes away from) the rewards would have been huge, both in renown and revenue. It absolutely made football and financial sense to make a go of it. Unfortunately, injuries and suspension scuppered us. C'est la vie.
I don't have a problem with any of our transfers, none of them are Robinho-type signings, nearly all of them have worked out and/or have significant resale value. The only ones with question marks for me are Wood and Lewis Hall. One we offloaded for £15m, the other is a loan deal with an option to buy.