France had UTA as there second full service carrier before it was merged with Air France plus the UK had British Caledonian as it's second force airline untill being merged with British Airways in 1987, so yes some European countries have had 2 full service airlines.
Both examples pre-dated the liberalisation of the European Air Travel Market and the rise of LCCs, and in both cases UTA and BCal where not sustainable in the long run once that it ended (they only ever where due to the fact they where designated routes they could serve and other airlines where given other routes, which is no longer allowed today)
The only example is Germany left and that is due to the Cold War (which meant LH could not serve West Berlin)