Many, many years ago I used to buy extra logic ICs...I still have a number of them (from plain TTL, to LS and S, to HC and HCT and some AC).
For many 6502/68HC11 SBCs I built in the past, I eschewed sparse logic for a poor man approach to programmable devices: I used a fast enough flash as a general purpose LUT to generate all the needed decoding and enable signal.
Nowadays, when I need a logic function I use a cheap and simple MCU (if speed is not of concern), ATtiny or similar - I'm not PICky.
If higher speed or prototyping is needed, I often go for the PSoC path...moreover so when some processing is also in the picture.
The PSoC creator schematic entry is not top notch but quite usable, so you can just layout your gates and pins, and change them as needed without turning on your soldering iron (Bob Pease might now be rolling in his grave
)
Only if the function is very simple, I buy logic ICs, though sometimes, after prototyping on a PSoC, I go back to a physical implementation relying on the generosity of my left over IC collection.
So, to conclude this boring tirade
:
Personally, I would not invest in stockpiling glue logic, especially if bought from Aliexpress/eBay or similar (as you say it take months to receive an order).