Such a myth. Not when:
- You have among the most cap space in the league in both 2019 and 2020
- You have two 3rd round compensatory picks coming in 2019 and likely another in 2020 (for Suh)
- You have a young QB on his rookie deal through 2020
- You have one of the brightest young head coaches in the league
Yes, things will get trickier once they sign Donald, Cooks, etc. They will need to develop 3-4 of their 2018 draft picks into starters and keep drafting well going forward. But they are hardly "all in" for 2018.
