While reasonable and logical, your proscription would result in a grievance filed by the players association that would be ruled on by an arbitrator and could result in the arbitrator enforcing the player contracts in full. That would cost the owners $Billions for nothing. They are better off not risking that and just use the limitations on gatherings above a certain size enacted by blue state governors to just cancel the season. That reduces their losses and more importantly reduces the potential of massive losses from an arbitration ruling going against them.
The average minor league player makes $1500 per month when the season is active, ranging from as little as three months at the Rookie or Pioneer League level to just under five months at the AAA level.
Obviously, every player has to hold an outside job the rest of the year, just like it used to be at the major league level.