You are all correct but really this should be in the STN thread.
Actually, for the purposes of a route to MAN then yes STN is a runway in the open countryside. But, as it's outside of 'London' there is a catchment for whom train travel isn't so quick.
Eastern, BA and Manx served the need well, and it ticked along for years with modest numbers paying extortionate fares for the privilege. As noted along came AB with fares a fraction of the price and the timings were pretty good. Of course, Eastern didn't stand a chance. However, the loads weren't spectacular as I recall, and that was with feed to the German routes. It didn't last, and when Eastern returned folk were less willing to fork out having been used to paying £40-80, not £250-£500.