The phrase "and therefore thinks" is correct and usable in written English.
It can be used to indicate a conclusion or belief that follows logically from a previous statement or premise.
Example: "She has always been a diligent student, and therefore thinks she will excel in her exams."
Alternatives: "and thus believes" or "and consequently assumes".
Trump knows this and therefore thinks he can say anything he likes.
It has demonstrated a proficiency at reasoning skills, and therefore thinks every problem can be solved entirely with that proficiency.
The tech establishment has solved, in a fashion, a problem that vexes the rest of America -- and therefore thinks about it in a way that seems to prefigure a larger shift.
Instead, she assumes they "just know," and therefore thinks there is no harm in sending messages during these times, because she figures they'll just be waiting for the employee when he returns.
This would be OK if the course changed a bit, or if there were some (any) kind of progression, but instead a relentless mill of contestants hurtle towards obstacles, fall, fail, and then get replaced by someone new and optimistic who obviously hasn't watched the show before and therefore thinks they can make it.
It's obviously somewhat of a mess, and Google certainly doesn't want to back down, and Aliyun is staying firm in the fact that it's NOT actually a forked Android OS and, therefore, thinks that Google is being unreasonable in its demands.
And some journalists couldn't conceive of how this guy could be involved in so many projects and therefore thought it was bullshit.
"However, we believe that there is sufficient momentum in the economy to avoid a double-dip recession and therefore think the Bank will refrain from implementing more QE".
Westerners saw good reasons for India to eschew testing and therefore thought Indians must understand their own best interests the same way.
He argues, "And therefore think him as a serpent's egg / Which, hatched, would, as his kind, grow mischievous; / And kill him in the shell".
