Appreciation should not require loss to become articulate.

Most people can speak beautifully about what they no longer have. The words were available the whole time and simply had no urgency behind them, and it is loss that supplies the urgency. Learning to speak that way earlier is possible, though it takes deliberate effort because nothing forces it.

Try saying the thing now that you would say in a eulogy or a farewell. Not all of it, and not solemnly, but the specific part. Tell one person what they actually do for you, in detail, while it is still ordinary to say so.