I agree with this 100%, Brexit and the plunging pound has totally destroyed this hobby for us in the UK. I'm just glad I got most of what I wanted before sterling crashed. Before I might have considered some of the SDCC offerings, now I'm only in for Yoda and R2 from HT and Snowspeeder Luke from Sideshow; I won't be buying any secondary characters and future 'instant buys' are pretty much limited to Jedi Luke if and when HT make one. At this rate things that I would have bought without hesitation like a HT Bespin Han or Emperor's Royal Guard are not going to be bought by me; I already have a Stormtrooper Han kit bashed from a spacetrooper and a Jnix sculpt.
It's hard to think what else I'd buy without hesitation - probably one of the Venkman's that's coming out, depending on which one has the better sculpt; I'd also get a licensed Daniel Craig Bond if Big Chief do one and its any good. But I won't be buying any random stuff at all - no Cumberbatch Doctor Strange, or Affleck Batman - which i might otherwise have shelled out for because they look like fun figures; likewise Muhammad Ali, a figure I've always wanted - now it's just too random given how much it will probably cost.
Then again I love what I do have, and maybe the pound will bounce back one day; I guess being forced to cut down also allows you to enjoy your existing collection more without forever thinking about what you don't have.