The anti-EU parties haven't given up on exiting the EU, they still have ideas and policies to reform it that would mean major issues for the project, the article itself points that out at the end. Neither is it as a result of seeing difficulties of the UK leaving, it's more about how each of these organisations wish to obtain the necessary power within their respective countries and siding against the EU at the moment would be the wrong thing to do, from their perspective, it's not a vote-winner. These nations are much more entwined in the EU from geographical and financial viewpoints and as such it will be a harder sell. They will probably bide their time until a possible economic downturn before EU-membership policies become more worthy of discussion and with the EU having to take more control over fiscal policies within the eurozone countries it could happen sooner than later, but hopefully not at all.