Hitler's agenda and motives were clear to everyone from day one, he not only never tried to hide them, he spelled them out in most of his speeches and in Mein Kampf.
The reason Hindenburg and his circle were willing to appoint Hitler as Chancellor is that they believed that he - an Army Corporal and high school-dropout, would be stupid and easy to control by elite military officer and technocrats. In fact, he proved to be much more clever and politically astute than they gave him credit for, and Hitler wound up running circles around his "betters" like von Papen, von Schleicher, etc.
There was also some aspect of desperation to the appointment of Hitler - had the Communists and Socialist Democrats been given more time and had they formed a coalition, they would have had a Reichstag majority and created a government - in which case Hindenburg and Co. would be stuck with a Marxist as Chancellor, something they wanted to avoid at all costs. There's also the fact that Hindenburg was physically and mentally rather frail in his final years (he was in his mid or late 80s when he died, I believe), so his ability to control what happened after Hitlers appointment was limited.
Hindenburg despised Hitler from the beginning, but thought he wasn’t a long-term threat....Ooops!
You are right with your posts, especially about Hindenburg (Prince Wilhelm, the grandson, would have been the candidate of choice for monarchists in those days). I just would like to comment a little on your statement that Hitler‘s aims were clearly stated in his book.
I have not read it (it was banned until recently over here), but it was never taken seriously by many. I think, when Hitler penned it in 1924, he himself didn’t reckon with his becoming powerful ever, let alone becoming an almighty tyrant.
Otherwise, he would never have so frankly outlined all of his aims.
The book was considered the work of an utter crank by most. Sadly, today we know how mistaken people were…
P.S.: By the way, the work Risiko Deutschland i.e. „Germany, the risk“ - I don’t know whether it has ever been translated - by the accursed greenslime Trotskyite Joschka Fischer, which he penned before becoming a successful politician, also was not taken seriously.
Today, we know that, in it, he outlined all the policies which his party implemented, and which commieb.tch Merkel continued (although she belonged to another party).
History doesn’t repeat itself, but it rhymes, as Mark Twain put it so well.