Given the evidence, it is a reasonable conclusion. Very little is ever "proved". Rather, we make conclusions based on the available evidence. If the evidence changes, we revisit our conclusions.
Whoever downvoted you, has probably never heard of the axiom: "Nothing can ever be proven true, because that means you would have to consider every possibility. The best that we can hope for is to prove something is not true by finding exceptions. After many failures at finding exceptions, we just state that some things are true until an exception is found."