Most games cost about £30-£50 to play new, take GTA 5 for example... It has never gone down or up in price in 4 and a half years... It doesn't mean that Minecraft is overpriced because it never gets old, like GTA... Games like COD and Battlefield will go down in price due to the fact of that they get old, except for BO3 of course :)
While it wouldn't be worth a full-price release, it fortunately isn't. It's around £18, which, for the game you're getting, is pretty reasonable. A game that has nearly no limits (especially considering the modding community) is definitely worth around that much. Of course, it's probably nowhere near as good nowadays, because Microsoft decided to say 'this is mine', but I'm still playing 1.7.10 thanks to the mods I have installed, so I couldn't really care less.
Maybe sometimes you need to install mods or texture packs, but that is really easy. Plus, compared to most other sandbox games of its size, minecraft is incredibly cheap. Plus it has over 779,054 lines of code. That is a heck ton for only $26.95. If you dont like this cost then go get minecraft on your phone or tablet or ipad. It only costs 7 - 8 dollars on there.
I have played mincraft once and the spiders were to kill and the myltiplay games were foul. It should be loward because my sister loves the game but she can't afard the money so in conclusion it should be loward so more people can play it and then more people can have fun