Collins is good. The Cowboys also benefited from getting him far cheaper than they should have as an undrafted FA all because of the strange story from his draft year. But...
But the money the Cowboys spend on the offensive line is already crazy. Before this deal, the Cowboys were already #1 in 0-line spending. The league average is ~$30 million, and the Cowboys were at ~$50 million before the Collins deal.
Zack Martin - highest paid guard
Travis Frederick - 3rd highest paid center
Demarcus Lawrence - 5th highest paid d-line
Zeke Elliott - 5th highest paid RB
La'el Collins - now the 5th highest paid RT
Waiting to be paid:
Zeke - will be #1 or #2 RB after his new deal
Dak Prescott - wants top 5 QB money
Amari Cooper - wants top 5 WR money
Byron Jones - wants top 5 CB money
The Cowboys simply can't afford to have the very highest paid o-line as well as top 5 paid players in every other position group as well.