A fact of life. Cost goes up.
The last 4 Dream Theater shows I've seen:
2009-10-09 - Manchester Apollo - £30
2011-07-23 - Wolverhampton - £34
2012-02-09 - Manchester Apollo - £50
2014-02-13 - Manchester Apollo - £62
That's not a reasonable rising cost. I've just bought tickets for 2 concerts at the Manchester Arena (a much larger venue, known for charging high prices) for £25 and £30, so I place the blame for these price rises squarely at Dream Theater's feet.
Remember the possibility that certain venues might have raised their prices. The ticket price consists of a part that goes to DT/RR and a part that goes to the venue.
Certainly doesn't look like the venue's fault. Here's some upcoming gigs at the Manchester Apollo:
Deep Purple - £41
Paul Weller - £43
Kenny Rogers - £51
Wu tang Clan - £40
Soundgarden - £42
Russell brand - £32
I'm pretty sure Jordan commented before the Dramatic Tour that the price rise was because of the more elaborate and expensive stage show they would be putting on. I was unimpressed, and the only reason I am going this year is because it's An Evening With. If the next cycle is a similar price (£50+) then I doubt I'll be going.