The short answer is no—an Xbox Live Gold subscription does not automatically extend to every account on the same console. Each Microsoft account requires its own Gold membership to access online multiplayer, free monthly games, and exclusive discounts. However, Microsoft offers a Family Sharing feature that can help households save money.
Microsoft's Xbox Family Settings allow you to create a family group (up to 5 members). Once set up, one Gold subscription (or Xbox Game Pass Ultimate) can be shared with up to four other family members. Each person uses their own account, but they gain access to Gold benefits through the primary subscriber.
If you're considering Gold, Xbox Game Pass Ultimate includes Gold, a vast library of games (including day-one first-party titles), EA Play, and cloud gaming. It's also shareable via the same Family Sharing setup. For most households, Ultimate offers far more value than standalone Gold.
For the latest details on family sharing and subscription options, visit the official Xbox support site.