I buy and play a lot of modern gaming. There are some months when it will beat out my vintage purchases, but probably over the course of 12 months, stuff I buy for vintage systems will total more. Homebrews and add-ons count as "vintage" or "retro" in this for me, so that is how I voted.
So going back to December, I've purchased some relatively high dollar items for vintage systems that are new creations
SD2IEC for C64
U1541 II for C64
Fastload Reloaded for C64
AtariVox for 2600
Fall Down 2600 H'brew
For modern systems, I purchased Alien Isolation on sale for XOne and some Steam items.
Of course, all of these things could be considered modern in which case the modern would far outweigh the vintage.