Maybe it's an add? I think it could be rewritten like this: "This allowed the remaining faithful consumers who are still clinging to its product concept, to always have a modern and innovative option and buy the newly improved product. "

The sentence doesn't really make sense. Where did you get it from?

the meaning should be: this thing (something I said before in the text) allowed the company to keep its "usual, classical conceptual line" in the production, while updating and adapting to modernity at the same time

"The sentence doesn't ..."

The sentences doesn't make grammatical sense to me but, to answer your question, the word "clinging" carries a sense of desperation. We talk about "clinging" to things that we fear will be taken from us.