You're making no sense and I don't think you understand the point you yourself are trying to make.
Let me go slow so you can understand.
A team has a limited amount of cap space. They must have starters at all positions, and they must have specialists. They must have backups, but rarely are backups starting caliber on any team at any position, because there is a cap.
When teams sustain injuries, they get weaker at those positions.
They do not get weaker because they 'didn't plan for it'. They got weaker because they cannot afford starting caliber players as backups, not to mention those players won't want to come to a team where they are backups.
If you are good enough, you overcome the injuries and still win with some lesser players on the field. Aside from a putrid OL, the Patriots were just that.
Players get injured, you need to account for that. Telling me you can't build roster depth based on past injury history is absurd. You absolutey can and you absolutely do. Why else did we carry 4 tight ends last year at the start of the season?
What position are you going to weaken to have expensive depth at WR? That's the only choice. So next year when a different position gets injured you will be railing all offseason about having twice as many starters as needed at THAT position.
For the last time, I'm asking to grab talented depth at WR. A veteran like Boldin and a solid #3 like Kearse is not destroying our cap. Not a bit.
Kearse is going to cost 8 million a year.
We need to sign players. The argument you are making, that the players we need to spend the most money on are the ones who will play if Gronk, Edelman and Amendola get hurt, comes with the consequence that you choose to hurt the talent that is out on the field at a different position in order to have depth at WR. What happens when the position you weakened gets injured?
Or are we just going to pretend that we can get whoever we want and there are no consequences to the rest of the roster?