IC Price Discrepancies (General Information)
There is a massive problem with counterfeit electronics, discretes and ICs. A quick search will show this to be the case. Counterfeiters will look at a) high volume, and b) high cost parts as that makes the most "commercial" sense for them. For the MAX7215, the volume is high. For the MAX6954, it's a bit less clear but to hazard a guess I'd say that that's banking on people choosing the MAX7215 because it's so much cheaper.

Your best bet is to buy through retailers, and not through AliExpress or eBay. This is no guarantee, but you're doing the best you can do personally. As to actually identifying a fake in your possession, it's very hard to do non-destructively. You usually only find out when something goes functionally wrong. If it's a hobby project, worst case is you have to replace some parts, but it's a huge issue when building critical appliances.

For example, here is a picture of the die in a fake MJ15004 power transistor. Note the tiny die - there's no way this will reach the rated power before it burns out! Credit to Elliott Sound for the image.