They're not mate, that's the fundamental in which I think you're wrong.
Look at it objectively. It's not a blip, we're just a poor football team;
I think we all can overcomplicate football but sometimes it can be simple and the players we have don't have the goals or assists in their game. They're just not there - that dictates any manager we have will be up against it fighting relegation.
If I felt this way, I'd agree with you, why sign players not part of a long term plan if we're sound anyway.
We're not though, this Everton team as it is go down. It would have went down last season if it wasn't for Richarlison, and Pickford. Richarlison is off, and if Pickford wants to leave he probably wont be at the very top of his game in any relegation scrap.
Short term measures are needed to a crisis, sometimes you have to plug holes. That time is most certainly now. The basis to build from is as a Premier League team.