the trades did bring flexibility. Absorbing Grant into a TPE is about as flexible as you can get
every year, some teams have cap-space; and every year, most teams without cap-space could use the full-MLE but don't because they don't want their flexibility restricted by a hard cap. That does not mean the teams are just sitting on their hands
edit. I just checked and I count a grand total of 11 players in the league signed to full-MLE contracts and that is over the last 3 seasons. Using the full-MLE is actually kind of rare:
https://www.basketball-reference.com/contracts/players.html