An alternative view is that National Pride reduces people's pressure to improve their country and especially reduces the pressure they put on the elites leading the country to improve it.

Certainly were I was born - Portugal - the peak time of celebrating the past glories of the country (basically, the stuff that happened during the age of maritime discovery) was during the Fascist Dictatorship, when the country was in such a bad state that it received Food Aid from the rest of Europe.

My own experience living in Britain also adds up to this impression: the people there who were most loudly proud of the country and its past where those doing the most to destroy it with Brexit.

A very similar effect is visible in the US - those who are loudest at harping about the greatness of the country are those helping the present day elites pillage it, de facto bringing it down (there is no such thing anymore as The American Dream).

In my experience National Pride isn't an incentive to do better, it's the very opposite.