I think the article is poor journalism tbh.
It states Southend as being an expensive fare to london, but it's the cheapest mainline rail link
It only takes 5 mins longer than the stansted express.
It's probably not that much further out than Gatwick as the crow flies.
And if anyone actually did a time comparison from landing to arriving in central London then Southend would win. Indeed I'd say if they took into account time spent in the hold etc it would do very well!!
As for Simon Calder. I'm afraid his views are generally old fashioned and very out of touch these days I find. Again, he's just a default go to for lazy newspapers.