Eclecticism in the Dhamma (as per AN 3.72; AN 3.65; MN 20) “Those who teach a Dhamma for the abandoning of passion, for the abandoning of aversion, for the abandoning of delusion — their Dhamma is well-taught”.
(Ājīvaka Sutta; AN 3:72)

Does this verse imply that the Theravadin tradition is sticking too much on traditional teaching, and are unwilling to accept other approaches as well? Rarely do I see monks for example, who acknowledge other approaches who aim at the removal of grees, hatred and delusion.
Of course the essence of Dhamma needs to be maintained &amp; practised, but if we take for example M20, as follows:

He should attend to another theme, apart from that one, connected with what is skillful.
If evil, unskillful thoughts — imbued with desire, aversion, or delusion — still arise in the monk while he is attending to this other theme, connected with what is skillful, he should scrutinize the drawbacks of those thoughts
If evil, unskillful thoughts — imbued with desire, aversion or delusion — still arise in the monk while he is scrutinizing the drawbacks of those thoughts, he should pay no mind and pay no attention to those thoughts. As he is paying no mind and paying no attention to them, those evil, unskillful thoughts are abandoned and subside.

With that said, it seems that there must not necessarily be a one-way approach, but rather, if 'x' fails do 'y' or 'z'. Am I misinterpreting something?
Regards
The Pali suttas say there is only one path to Nibbana. 


  273. Of all the paths the Eightfold Path is the best; of all the truths the Four Noble Truths are the best; of all things
  passionlessness is the best: of men the Seeing One (the Buddha) is the
  best.
  
  274. This is the only path; there is none other for the purification of insight.
  
  Dhammapada