You've conflated two issues in this post, and moved the goal-line in the process.
Your headline says "Why does Ballard love 1-year deals"... and you list a large bunch of players who have received one-year deals.
But you've also lumped in with them, a bunch of players who are NOT one 1-year deals. They are on the last year of their rookie contract. Their 4-year rookie contract. That's entirely DIFFERENT. You listed, Hines, Wilkins, Smith, Turay, Lewis, Adams and Franklin. That's 7 players who are on the last year of their 4-year rookie contract. You even included Glowinski, who is on the last year of his 3-year deal that Ballard signed him to. 8 players. And they've all been lumped in with guys who got 1-year deals.
The reasons for all the 1-year deals are several. One, 1-year deals keep motivation high. Two, 1-year deals can be done with players at a young age because you have contractual leverage, like with Pascal and MAC and Odoms. Three, one year deals during this current strange Covid time is because the salary cap has gone down, no one is quite sure how much it will go up next year? So, better to do a one-year deal and then figure things out in a year or so when we all have a better idea on what the 22 cap will be and even the 23 cap. Four, things are going to get complicated, financially speaking, when we sign guys like Q, Darius and Braden to their Big Deals. Plus, by then we might be talking about extending Wentz. All that will be a big factor on our long-term approach to the team.