You're talking like Google's a minority player in this deal. Google's the big dog here. Google dictates terms, and this one isn't so onerous. They patch the OS and they send the patch to a bunch of handset makers. They integrate the patch and push the update. This isn't a fundamental system overhaul, it's a bug fix. Unless the phones are incapable of receiving an update at all, they should be able to get this no problem. If there are costs, Google can offer to defray them. This is about building a brand and taking care of your customers. All this is doing is further pushing the perception that Apple takes care of its customers and Google and it's partners don't. Samsung is the only one that could theoretically afford to turn Google down because they could switch to Tizen, but they're getting drubbed by Apple at the top end and Xiaomi at the bottom; I don't think they're in a position to make a afuss.
But if that's what they want, that's fine--I'm an Apple shareholder (20 whole shares!) and that just makes my stock more valuable. And I own an iPhone and will continue to buy them. Whenever I look at Android, one of my big concerns is how long I'll get updates. If this is the sort of thing I can expect--buy a new phone for the latest security patch--I'll continue paying $700 for an iPhone and getting updates for 4+ years, thanks. I'm sure I'm not the only one.