I don't expect anyone else to build me a FOSS email client. I do expect that by 2015 somebody would have figured out a way for me to give them money for a good email experience. :)
If you own something, you're not buying it - so the seller doesn't get the money. Software figured this out quickly - that's why everything that has not moved to cloud yet is being sold in form of licenses - a temporary grant to use some software. Rest of the world did it with planned obsolescence, and now the trend is to actually make you license hardware instead of buying it. It's sick. But that's where the money is, that's what the Market[0] says to do, therefore it's happening.
[0] - or Moloch.
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I'd like Inbox-like features theoretically, but the fundamental UX/UI is done better than anyone else IMHO.
- Open Mail, roughly time how long it takes from left pane click to message fully rendered on the right (~2-3 seconds)
- Open Dropbox (fast before it goes away!) and do the same (~250ms)
I get roughly 100-150 emails overnight that I go through in the morning. At 2-3 seconds PER THREAD render this is insanely unproductive use of my time.
Every time I open OSX Mail I have this exact process in my head and I promptly close it.
I'm also talking about my iOS experience. There are some perf issues that would be nice, but for me that's mostly in search and initial sync than stuff that's already downloaded.
Inbox by GMail has some of the ideas from the Sparrow team incorporated in it, but it's only really usable on mobile. (The desktop Inbox web app is awfully slow compared to, say, GMail or Outlook.com.)
When Hotmail came out, who still paid for Eudora licenses?
That said, if a decent email client is that important to you, don't underestimate the impact you could have building it yourself as open source on evenings and weekends. And if you don't think it's worth your time to do that much, why would you expect anyone else to?