If NUFC hadn't spent the 40 million on Joelinton and put it into the infrastructure there would have been absolute hell on, and you know it. The fact Joelinton hasn't worked (thus far) means you can use this as something to back up your statement because it suits you agenda. I can also guarantee that if Joelinton had been banging the goals in and had you around the top 8, the academy / infrastructure at present wouldn't even be mentioned.
Since 2007, The Premiership has had 42 relegation positions available, Newcastle have occupied these finishing positions, twice, in 14 years. There is not one of those clubs who have been relegated (or some of them who haven't even been relegated) twist, moan, and continuously blame the owner for absolutely everything that has happened within that time period. One of the unique things with NUFC is within that time period they have also had some successful seasons, again which is then classed as fluked or nothing to do with the owner at all. There is also clubs who have been relegated and never returned, and fans of these clubs don't kick and scream like petulant children because the owner isn't ploughing money back into the club (when he has already stated on many times that he can't afford to do)
So in short, no evidence whatsoever.
Isn't the job of the academy to develop either a) players for the first team (Which you have done) b) generate income to the club (Which you have done) - You completely ignored my question here. You haven't released an academy product that has went on to have a really successful career, From the ones that have been developed to a level you are at, You have either got significant money for, or they are part of the first team squad.
Every single appointment in football is a gamble, There is absolutely no guarantee that any appointment / signing will always work. You can obviously mitigate the risk but there is no evidence to suggest that when Ashley appointed some of the more successful managers i.e. Hughton, Benitez, Pardew, that these appointments weren't carefully considered behind the scenes, again because it doesn't suit your agenda, your assuming they weren't. You will no doubt come back and say Pardew was appointed following on from L1 in Southampton, yet his appointment was actually pretty successful, you can't have it both ways.
If you are not asking for Ashley to put his own money, yet you wan't him to invest in the club, How do you expect him to do this significantly when the club over the last few seasons has spent what it's brought in?