Yeah this is spot on - you've pinpointed what the actual gamble is. Boehly et al are betting on themselves and their past experience in improving commercial revenues. As you say if it stagnates it may become problematic.Yeah these long contracts are actually reasonably smart, Boehly is taking a leaf out the NFL playbook where contacts have lower cap hits in the first year or two and then increase in later years. That's viable because income tends to go up over time.
So Boehly is spending big now to increase their brand value and revenue. Of course if most of the players flop and broadcasting income plateues (which it has done for the next 2-3 years) then it could be an issue for Chelsea.