I found this quote from the article to be particularly interesting:
If, for example, someone received today a floppy disk or a Sony minidisk from the 90s, it would be very hard to find a device able to read it now. It is likely that the same problem will happen with USB sticks, so using a hardware wallet from 2019 may end up requiring multiple adapters to bridge between different communication standards.
And it made me wonder whether in 18 years, when the gift recipient has grown up, bitcoin will be as popular or as relevant. It's a technology that might not age well in that amount of time--and I don't get the feeling that it's going to disappear or anything like that, but you wouldn't expect USB drives to disappear either. People expect long-term growth from bitcoin, but the truth of the matter is that none of us knows what's going to happen in crypto.
Having said that, I think it's a fantastic idea to put aside some satoshis or whatever amount of bitcoin would be appropriate for a newborn. It's a cool gift if nothing else.
Give me floppy disk full of bitcoins and I'll make it readable for me, I saved old floppy reader from my very old pc do not a problem for me

I think time isn't a huge problem, if old device has something small common with new one, then it won't be a problem.
That's really a good question whether bitcoin will be popular in 18 year or not. Technologies develop, things are getting older but at the same time everything new is a well forgotten old and it's really true. I think bitcoin won't be so popular and there will be another altcoin that will take it's place. I know a lot of people will come now against me but it's truth, the only way to get rid of it is to add new features on bitcoin and change it as time goes.