It’s pretty safe to assume that at this point every fricking pilot out there knows about MCAS and how to deal with it if this specific problematic behavior occurs.
It's been happening during initial ascent, which is a very busy time of flight with little margin for error. Even if you are aware of MCAS, it takes time to recover, and you might not have that much time to spare.
It's 2.5 degrees every 15 seconds. There's time to recover
"MCAS will trim the Stabilizer down for 10 seconds (2.5 deg nose down) and pause for 5 seconds and repeat if the conditions (high angle of attack, flaps up and autopilot disengaged) continue to be met. Using electric pitch trim will only pause MCAS, to deactivate it you need to switch off the STAB TRIM SUTOUT switches." http://www.b737.org.uk/mcas.htm