In general I completely agree with this article, unless the collectible generates value in itself and is limited. For example film cameras and more rare medium format digital cameras are appreciating now quite a bit, above original MSRP
Most stuff never goes up in value. Most technology, even the famous/popular stuff has only gone down in value. With a few exceptions of things which were later seen as iconic but rare. Stuff like the original Nintento gameboy can be bought now for less real value than they were new. Almost certainly because there are so many around. So you have to be a fortune teller to work out what item will be more popular in the future than it is now.