A max capacity of 250 passengers will make the tickets prohibitively expensive and people will opt for a cheaper ticket with a stop over.
Singapore Airlines SIN nonstop to JFK is premium economy and business/first only. No standard economy. This in turn makes the cheapest ticket double the price of Cathay and Turkish etc.
If SYD to LHR non stop is $4k, but I can get it for 3k with a stop in Singapore/Dubai etc I am taking the stop.