I do think that Microsoft will eventually offer a bundle, but no, Game Pass doesn't "already handle that" when you consider the differences in ownership. With Game Pass, you have access to a rotating selection of games while they're part of Game Pass. With Xbox LIVE Gold, you retain ownership of all Xbox 360 games that you download as part of the service, and you retain ownership of all Xbox One games that you download as part of the service as long as your Gold membership remains active. They're completely different things. Frankly, I find it odd that people continue to complain about this when you consider the value proposition (because of the free games) and the unquestionable superiority of Xbox LIVE over PlayStation Network from a reliability and security standpoint.
Also, you don't *have* to pay for Xbox LIVE Gold. If you use Bing and Microsoft Rewards, then it's very easy to earn free Xbox LIVE Gold on an annual basis.
I do wonder if we'll see brand new games from third parties get a temporary gamepass release or multiplayer centric titles get occasional free months on gamepass prior release of expansion content to promote the release.