Whenever it's a new game that I'm paying full price then I buy retail. The main reason I buy physical copies is for easement of modding if I ever have the need. I have not used a mod in ages though. Other reason for physical copies is I don't want to concern myself with the distribution service ceasing to exist.
When I have a game on my wishlist it is because I'm not convinced enough to buy the game...or convinced I want to spend the money. Thusly when Steam does its sale events I'll grab games from Steam.
Nowadays I do wonder if I'm going to continue with physical copies. Internet connections are not nearly as terribly slow. I remember downloading patches at 100kb/s or 200...and that was considered fast for me but dang that took forever (hence the physical copies).
Lastly my disc drive died years ago. Fortunately physical copies tend to come with Steam keys inside the box so I don't even use the disc. In the event Steam ceases to function I at least still have the disc. And I like to look at my game collection now and again. Whenever I move my closet of boxes it's a bit of a nostalgia trip