An untrained cyclist is not able to maintain 200 watts.
For an average untrained male cyclist who is 175lb, they should be able to maintain 1.5-2 w/kg over an hour, or 120-160watts. A beginner cyclist who's been cycling recreationally over over a year should be able to attain 2-2.5w/kg which is 160-200 watts. A recreational cyclist who's be training for several years should be able to maintain 200 watts.
Trust me, I'm a cyclist, and I cycle with a power meter.
Just one more follow up and I'll be done, promise. The average power output (FTP) of someone on zwift, a indoor cycling game, is a whooping 185 watts.
As an average male who is ~175lbs and untrained at cycling, this is hugely validating for my terrible idea; 140 watts is the max charging speed for 16" M5 MacBooks. I can finally stop thinking for myself and have my computer do it all for me, powered by my big beefy legs.