Okay, so it's the tenses that have you confused. Lets first break it into the clauses that use the past and that which use the present, check each of them, and then check that the combination works.
Surely, we can experiment with various styles, combine genres and produce eclectic output, but let us face the truth:
All in the simple present. There's a change to the imperative mood, but that's fine, and the rest seems straight-forwardly correct.
... the strategy was exploited so frequently before, that it has long lost its originality.
Past ("was exploited") followed by present perfect ("has...lost") to describe something started in the past and continuing into the present. The flow from one to the other is clear and reasonable, the past progressive says what has happened over a period in the past, and the present perfect describes the consequence, in clearly separate clauses joined using that. Again, this is fine.
These two are joined by a colon. That's fine, they could be independent sentences, but the colon expresses how one follows from the other.
And here, that degree of independence allows the combination of very different tenses. So fine again.
The only objections I can think that people might make are:
Splitting the present perfect ("has long lost"). Some people object to this. It's a generalisation of objecting to split infinitives, and even sillier. It's the sort of objection where the people who make it will still do it themselves, because they don't really believe it, they just worry about it. So, while I know such people are out there, I don't agree with them in the slightest.
Lower-case letter after the colon. Some people will say that you should always capitalise after a colon. Some people will say you should never capitalise after a colon unless it's a quotation or more than one sentence. APA would say it was wrong here, CMS would say it was correct (it allows either). When we have such disagreements we can safely say it's grammatically correct, just not to some people's style.
So, all in all, I don't find anything wrong with it.