People can buy digital subscriptions if they don't want to use paper. But some people want hard-copy magazines, and it's not wrong for us to offer them. We will do our best to use sustainable paper sources and responsible printers.
As for the costs, those are normal in the publishing world. Many magazines have tried slashing the contribution per-page cost, and ended up with poor quality content as a result. We want the best contributors, and they're worth paying for.
100GBP per page may seem like a lot, but that's for 800 words of highly technical content, that has to be correct, well-written, informative and entertaining. A single page can take many hours of work when you're dealing with advanced subjects. You get what you pay for.