As the article states, I agree that the salary cap isn't going away. The calculations may change, but the cap is required to keep the small market teams competitive and the wealthiest owners from dominating.
Guaranteed contracts will have unintended consequences. If this becomes a requirement, teams will be less willing to sign longer term deals as the risk increases in the later years. Total contract value for many players will likely decline as well. Maybe this is worth it for the players, maybe not. But these seem like two obvious impacts on contract negotiations if guarantees are mandated.
