Newcastle still needs to improve the squad instead of letting some of its best players leave at the end of the season. Alexander Isak is one of the important players in Newcastle's squad this season, so they need to keep him instead of selling him. It is true that it is difficult for Newcastle players to hope for a title, but it is not impossible for this team to follow in the footsteps of Manchester City because of its good financial strength.
This season Newcastle's performance is very different compared to last season, even though they have improved their squad. Of course player injuries have had a significant impact on the team's performance, but that should not be the main reason why they have dropped so much so far.
Newcastle need to let players leave not because they willingly want to but because they need the money and also clear the wage load from this quality players. Last season Newcastle Qualified for the champions league which the bonuses received from the group stage matches were used to cover for the profit that should be meet in accordance to how you spend (mostly wages impact this). But next season without something like European football, it will be hard to make same profit like this year and the amount spend on this current players wages will be higher than the net profit earn which will lead them to been sanctioned like they did to Everton. So in other to avoid such clubs usually lower down there wages and by selling quality players they get more money to also cover for the profit to be made. That’s why clubs result in selling off their important players sometimes