las claves de turismo

Hello again :)

I find this forum very useful and I would like to thank you so much for your suggestions. I am just so grateful that I can consult my translations with you.

In the same text, I've encountered the term "las claves" which I've then found in many documents on the internet. It seems a very common word but yet the translations offered by dictionaries do not suite any of the contexts I've found. I have a general idea of what it means I am just lost how to put it in word(s). I would appreaciate your suggestions, especially since I am not native to any of the two languages in which I am translating (Spanish, English).

"Todo indica que las claves que han sustentado el turismo espanol desde los anos sesenta estan agotadas y que una serie de temas centrales estan alterando de forma sustancial sus cimientos."

My attempt:
"Everything points to that the leading factors that have sustained Spanish tourism since the 70s are exhausted and that a series of key topics is fundamentally altering its foundations."

Thank you so much

No entiendo muy bien el español. ¿Temas? Pero estoy seguro tiene razón. En lugar de temas, entendía mejor “cambios”.

Everything indicates the leading factors that have sustained Spanish tourism since the 70s are exhausted, and that a series of key topics is fundamentally altering its foundations.

Si puede cambiarlo un poco:

Everything indicates the leading factors that have sustained Spanish tourism since the 70s are exhausted, and that its foundations are suffering fundamental changes.

"Todo indica que las claves que han sustentado el turismo espanol desde los anos sesenta estan agotadas y que una serie de temas centrales estan alterando de forma sustancial sus cimientos."

Everything indicates that the strengths which have sustained Spanish tourism since the nineteen-sixties are spent and that a range of key issues is changing the underlying situation substantially.

NOTE.

"Turismo español": Ambiguous. Is it domestic tourism or foreign?

Oops. A slight ten year error on my part.