What could The Flex Offense possibly have in common with the Read & React Offense?

Actually, they both have several things in common:

All players learn all the positions, or you could say that they are both “POSITIONLESS”!
Everyone knows where everyone else should be and what they should be doing at all times = High ACCOUNTABILITY!
The CONTINUITY of basket cuts, screens, and changing sides of the floor, will create a defensive breakdown. Often times, I hear Flex coaches and R&R coaches saying the same thing: “Just take care of the ball and turn the offense over and the defense will make a mistake!”
The PRIMARY threat is a Lay-up, i.e., the offense constantly “threatens the rim” and DEFAULTS to open jumpers or open drives.
So what? Why point out similarities? Because since the Read & React is so unlike any other offense, coaches have a difficult time explaining when it’s introduced to new players. If you can start with something that is KNOWN (like the Flex or your Set Plays), it becomes easier to move to the UNKNOWN by association:

“It’s just like what we used to do when it comes to Continuity, Accountability, etc…”

Once you break through the natural resistance that comes with learning something new, you can sell them on the DIFFERENCES:

“Unlike the Flex, (or whatever offense they are familiar with) the Read & React:

Is unpredictable – there’s no pattern for teams to scout.
It’s flexible – formations, tempo, ways to score can change based on personnel.
The Read & React can be used against zones – no need for a separate zone offense.
It can be extended to the Full Court to break presses and traps.
Equip your players to believe!