@vserian
The 200LRs that AI has seats 238 pax in a 3 class config. The 787-8 is expected to seat 210-250 in a 3 class config. So no advantage in terms of seating capacity.
The 200LR has a range of about 1000NM more than the 787-8. But since we are talking about long haul sectors (LHR, FRA, CDG etc.) and not ultra long haul this extra 1000NM range is useless.
The 787-8 is much lighter than the 200LR since it made of composite material. So for example on a DEL-LHR flight with 230 pax the 200LR will consume more fuel as it is heavier and has bigger engines.
The 787-8 is about a decade ahead of the 200LR in terms of technology and operating cost are hence lower.For example the elimination of the pneumatic bleed system on the 787s which would mean the engines need to produce less thrust and hence burn less fuel.
The GE90 engines on the 200LR which produce 110,000 lbs of thrust consume more fuel than the GEnx engines on the 787 which produce about 70,000 lbs of thrust.
So for the same seating capacity with range and payload not being a constraint the 787-8 will beat the 200LR. Unless AI intends to use the 200LRs higher MTOW capability and increase the seating capacity to about 300 then it might be a different story.