That's true, things are always evolving, however, so far, it seems that in Europe the current consensus is that children of a monarch are princes and princesses, regardless of whether they are full-time, part-time or non-working royals (and in some royal families this also applies to either all or male-line grandchildren). In most cases, they also are royal highnesses (or serene highnesses if applicable). Norway is the exception.
Belgium: both siblings are prince(sse)s with the style of royal highnesses
Denmark: sibling is a prince with the style of royal highness
Liechtenstein: all siblings are prince(sse)s with the style of serene highnesses (same as Fürst)
Luxembourg: all siblings are prince(sse)s with the style of royal highness
Monaco: both sisters of Albert are princesses; one with the style of serene highness, the other as royal highness due to her marriage
Netherlands: surviving sibling is a prince with the style of royal highness
Norway: sibling is a princess but lost her style as royal highness (which is also applied to the next generation; who never was royal highness)
Spain: both sisters of Felipe are infantas with the style of royal highness
Sweden: siblings are prince(sse)s with the style of royal highness
United Kingdom: siblings are prince(sse)s, brothers are also peers/dukes, all with the style of royal highness
True, but in Europe there is also a general consensus that children of a monarch work only for the monarchy, state, or family and/or refrain from making money through private business, so it makes sense that titles still reflect the current situation rather than the possible future trends:
Belgium: The full siblings of King Philippe (born 1962 and 1963) are part-time working royals in receipt of dotations, and it remains to be seen whether his younger children (born 2003-2008) will become part-time working royals (but Parliament has decided they will not receive dotations).
Denmark: The sibling of King Frederik X (born 1969) works full-time for the state and receives a dotation, and it remains to be seen whether his younger children (born 2007-2011) will become working royals, though the intention is that they will not receive dotations.
Liechtenstein: The brothers of Hereditary Prince Alois (born 1969 and 1972) work(ed) for the Liechtenstein family companies; his sister (born 1973) is a homemaker. I am not informed about his younger children (born 1996-2000), but in any case there is still plenty of time for them to join the family firm if they have not already.
Luxembourg: The brother of Grand Duke Henri who remained in line for the throne (born 1963) was a part-time working royal during the previous reign and his sisters (born 1954 and 1957) were homemakers. The siblings of Grand Duke Guillaume (born 1984-1992) have private business careers.
Monaco: The sisters of Sovereign Prince Albert II (born 1957 and 1965) were/are part-time working royals; I believe the Prince has said his daughter (born 2014) is expected to support her brother as well.
Netherlands: The sibling of Queen Beatrix (born 1943) and the sibling of King Willem-Alexander (born 1969) who remained in line for the throne were full- or part-time working royals. It remains to be seen whether the sisters of the Princess of Orange (born 2005 and 2007) will be working royals, though they will not receive dotations.
Norway: The sibling of King Harald V who remained in Norway (born 1932) is a part-time working royal. The sibling of Crown Prince Haakon (born 1971) had the option to become a working royal but chose to become a fully private businesswoman. The crown prince has said his younger son (born 2005) is expected to become a part-time working royal.
Spain: The siblings of King Felipe V (born 1963 and 1965) were part-time working royals during the previous reign; it appears his younger daughter (born 2005) will be expected to do the same during his reign.
Sweden: The siblings of Crown Princess Victoria (born 1979 and 1982) are part-time working royals; it remains to be seen what will happen with her younger child (born 2016).
United Kingdom: The siblings of King Charles III (born 1950-1964) and the sibling of the Prince of Wales (born 1984) were/are full-time working royals. It remains to be seen what will happen with the younger children of the Prince of Wales (born 2015 and 2018).
Thus, I would say Luxembourg is the only European monarchy which has already established as a general rule that younger children of monarchs will not take on public/royal duties
and will be free to earn their living in the business of their choice, although there have been individual cases in other monarchies. But for better or for worse, there will probably be more children of monarchs following that path in the near future, and it is not unlikely to happen in Denmark, especially as Isabella, Vincent and Josephine already have the example of their cousin Nikolai.