Plane daft. Being at the gate 30mins before departure means before the inbound has arrived, sometimes. Plain stupid. Surely the decision to board, with no checked baggage, should be made at the gate. You are either there or not. KISS.
With checked baggage and squeezing the time to the gate can involve a baggage search and delays. That's anti-social and bad etiquette, but not uncommon. However, for the supposed 'train in the sky' business model (see SWA) it seems un-attractive and not inviting to pax.
The logistics defeat me. Check-in closes 45mins before departure. Queue at security is 20 mins. You are denied boarding because of the fault on slow security; AND it is their fault.
Flight delays might allow some leeway? That's an interesting one. How updated will the security gates be? On one of the easyjet TV episodes a family attending an important family event in S.France were delayed on M1. They arrived before STD but later than 45mins. They had phoned a friend on board to tell them of their late arrival. They told them there was an hour slot delay. Checkin were rock-solid; not possible and then blamed the captain that as the doors were closed he would not accept them. No sympathy, no discretion, bad advertising. This seems to be an extension of that. The company is designing a model to suit itself hiding behind the 'benefit to customers'. Good customer service needs discretion and intelligent people to exercise it. When to be hard & strong and when to be soft and gentle. As long as the goal is achieved who cares? Oh yes, the customer.
And why just LGW? Why not MAN/FCO/CDG/MAD/etc. eat. These airports have a very long walk time to the gate.