I had an email exchange with Efe in the early years. He seems like a nice guy and I got some free membership trials out of it. Back when it only used to cost £3 p/m(!)
Re: the film. I imagine it's hard to get rights to Wong Kar Wai movies. For years they were done by Artificial Eye, but then they were bought by Curzon which runs its own online streaming service, so probably isn't keen on selling the rights widely (or for cheap). They price gouged a lot with the recent blu-ray collection, for example. Currently retailing at £150 for 7 films
Re: the service more broadly. I think it's obvious where MUBI's issues are when it comes to distribution and why they only get rights to certain movies. They'll pick up on a lot of older movies that either have cheap or lapsed rights. When it comes to newer movies, they clearly try and get exclusive rights for films that don't have physical distribution in the UK.
A lot of these then end up being Europeans movies - ones not currently distributed by companies like Curzon/Artificial Eye. I know with Japanese movies, for example, they tend to be a bit crap because they're usually handled by Thunderbird (good relationship), Eureka (good relationship), Third Window (minimal relationship), or Arrow (none, similar to Curzon). Adam Torel at Third Window does a podcast and has explained that they prefer to go their own route, either distributing via Amazon or a sister service like Terracotta Distrubition (via Vimeo).