'spying' is perceived as boring or 'it happens anyway' or 'we cannot do something about it'. Of course you can. You have the choice to be slightly less lazy and actually use the alternatives where you can&want, maybe even if they are worse! I'm not implying here that Thunderbird is worse than gmail ;)
Furthermore 'spying' should not have the personal touch (only). Instead companies should take this issue really serious to reduce the possibilities of econmic spying. I know companies fighting hard against Google with their products, having strict NDAs but then yes, they use non-encrypted gmail accounts for everything.
Thunderbird is important like all of these alternatives (be it open source or not like DuckDuckGo) to reduce influence of monopolies. As monopolies are bad for users&customers. Always.
BTW: you can donate here: https://donate.mozilla.org/en-US/thunderbird/
But the trust can be broken. Which was my point.
http://penguindreams.org/blog/how-google-and-microsoft-made-...
Then again, towards the end of my time with Gmail, I'd still have friends tell me mail sent from my gmail address ended up in spam. So maybe e-mail is just shit now.
That said, if you want a web-hosted client for standard email, why not give self-hosting RainLoop a try?