“Are modern prices justified” has been a question on here since probably early 2020. In one sense, absolutely these prices are justified. You have a huge amount of people who are motivated modern collectors, and who are spending large amounts of money. Modern collecting is the most important reason for why the Pokemon hobby is as healthy as it is right now. I think a lot of us who have been around for awhile are skeptical of modern cards because of their sheer print numbers and how different the market feels now compared to even 4-5 years ago. However, most of the new fans that are getting into Pokemon are getting into modern, not vintage.
A good anecdotal example is my girlfriend. She’s the same age as me, obviously knows about Pokemon since release but was never really into it. But her family and I are fans, so she’s gotten interested over time. Her most wanted cards are all SWSH special arts, especially Moonbreon and Gengar VMAX alt art. She thinks vintage is boring.
The dynamics have changed. It isn’t just kids getting interested in cards anymore, where we need to wait 20 years for the kids to grow up, get disposable income, and then buy the cards up again. Interested adult collectors with deep pockets are driving modern prices. If that dynamic keeps up, I see no reason why modern cards, especially the most desirable, won’t be extremely strong in the long-term.
That being said, these modern prices are predicated on the highest level of demand which Pokemon has ever seen, perhaps save for the original Base Set release. The print numbers are massive. I would say that modern is much more risky than vintage, because if the market dynamics shift again and demand decreases, modern is more susceptible to this.