I reckon that this hobby, HiFi Audio, is a terrible hobby financially.
At least with hobbies like mechanical watch, or cars, there is a chance some collectibles may hold on to its value and some may go up in value.
With audio, Gosh, have you tried to sell in the used market post-COVID? It's a disaster.
EDIT: See post #4 for further clarification
It is absolutely absurd to view hobbies as financial investments. Really, only husbands and nerds do that to justify their hobbies.
Watches are a good example. Among my friends and acquaintances, 95% of the watches purchased as investments have plummeted in value, suffering huge losses over a period of 35 years.
The same thing happens time and again with many other collecting hobbies—Kinder Surprise toys, art, jewelry (branded items), Lego, Snickers, etc.
Even with decades of experience, no one can predict with 100% certainty which items will retain or increase in value, or when and for how long that might happen.
Especially when buying new items, you have to assume they will immediately lose at least 30% of their value.
For the value to rise again, a lot of factors have to align: high technical value, high sentimental value, low production numbers, limited availability, and far more interested buyers than available items.
In the audio sector specifically, I consider an increase in value for expensive items to be completely unrealistic.
There may be exceptions, but certainly not many.
In fact, my CD player collection has at least doubled in value over the last 6–8 years, though that will likely drop again. However, we are talking about players in the €50–€300 range (used). With more expensive units, it would have resulted in a loss on average.
But I don't own my CD player collection for the sake of making a profit.
But if you ever want to try out truly expensive hobbies, I’d recommend things like RC F5B—with the goal of competing—or RC quadcopter racing, or RC F3C/F3N/F5C, and so on.
Be prepared for five-figure annual budgets (and not at the low end of that range), and don't expect to see any of that money back.
That’s what a hobby is.