Yes, it's changing. Fortunately 'my' branch of the family picked 'ij' so we're in the clear ;) But for some of the older members it is causing all kinds of trouble, especially when interacting with the authorities, more so if one set of documents uses 'ij' and another through accidents of history uses 'y'. Some schools even teach 'ij' as the 25th letter of our alphabet, when they really should be using 'y' for that spot and 'ij' as a two letter combination.
Also, when spelling words people use 'ij' as a single letter for instance a Dutch person would spell 'mijn' as 'm', 'ij', 'n' (and they would likely not say 'lange ij' because there is no word 'mein' in Dutch.
It also causes no end of trouble with storing and searching because a Dutch person might expect IJ to be sorted after 'X' but instead it appears sorted as the combination I J . The fact that different reference works use different methods doesn't help either.
> for instance a Dutch person would spell 'mijn' as 'm', 'ij', 'n'
Not anyone under the age of fifty, unless they want to deal with the follow up question too. ("Is that a long or short ij/ei?")
Here's a screenshot from just one random Dutch children's spelling quiz online:
Separate letters for 'ij', despite it formally being a single letter.
The only place where the difference between 1 letter and 2 letters still is visible is in names that start with a long ij, because of the capitalization. E.g. the name of the city IJmuiden is written like that and not as Ijmuiden.
In handwriting it's written as one character, but I think that's just a ligature: https://nl.wikipedia.org/wiki/IJ_(digraaf)#/media/Bestand:IJ...