What is happening is that Merlin are reshuffling their budgets for the 2018-2021 period. So, £100m of money that was going towards Capex investments at the theme parks and current midways is now being redirected to focus on new accommodation (ie hotels), new Legoland parks (New York in particular being a focus) and new midways.
There is still money that will be invested in the parks. There will still be new rides and stuff. And this budget reshuffle doesn't affect things like current staffing levels / operational costs. It's a case of there will be a less of it, and not as large an investment. It's major - effectively £25m a year across the parks and midways is A LOT - but it isn't a case that investment will stop completely.