The answer straight away: No.
The most dynamic nations regarding economy, science and arts on this earth are multicultural.
This includes nations like the the USA, Israel, Canada, Australia and almost all EU countries and. Additional to this you also can see China and other emerging powers like India or Brazil as quite multicultural.
As contrast: Anywhere where one “authoritarian culture” tries to block all the cultural influences from outside, stagnation and decline is more likely.
You can see that in most Arab countries, North Korea, Pakistan and in general, in areas where one group tries to ideologically or religiously particularly stay “clean”.
Not to long ago, many heads of states with a multicultural policy -mainly in Europe- declared their political approach as failed.
Since I am from Germany, let us focus on this case.
To quote Chancellor Merkel: multiculturalism had ‘failed utterly’.
Yet, it is more concrete that there is a long history of success, which just needs a new adjusted framework, not only to support immigration and migration but also challenges its participants and prevent parallel society-system within a state!
Nowadays one out of five people in Germany has foreign roots and the proportion of people with foreign origin is increasing – and so is the need for more money for education.
This was completely clear from the beginning!
An economist could tell you this without thinking. With the target to make profit, you need to invest your money.
The history of Germany always was, is and will be characterized by German citizens emigrating or foreigners immigrating. This can be for work, housing, marriage, wealth and cultural reasons.
In addition to that the first half of the 20th century with its millions of forced migrations during and following the two world wars created a even more multicultural society, which was working very well.
Learning from that, the key of multiculturalism comes from the efforts, not to separate but to integrate and still provide freedom for own cultural aspects.
Only then, when there was a successful integration, the enrichment opportunities due to multiculturalism can be realized.