It is a very abstract term. It is like ”democracy”. Yes, you can clearly say that North Korea is not a democracy. But US? Well, depends on who you ask.
Same with welfare state. Which countries do you count as non-welfare states? And when do they stop being a welfare state? Let’s take Poland as an example. When do they stop being a welfare state? If they lower the unemployment payments, will they stop being a welfare state?
And at what timescale do you think Poland will stop existing because of demographics?