Are these English tests, viz., IELTS, PTE, Duolingo, etc difficult? Why do so many students do not get satisfactory grades despite studying diligently?

Englist tests appear difficult as the number of questions, just like any other competitive exam, are numerous and even the 3 or so hours alloted appear less to attempt all of the questions. Some of us have our own learning curve. Give me sufficient time to answer at my leisure and I will turn a 100% correct answer sheet, at least in English, that is. Sometimes it appears that they are out to test our IQ levels rather than English. The tought world of competition they make it out for us students is an illusion. In life you can achieve anything if you have the hunger. And no, time does not run away, nor does your completition get ahead of you. If you do what you love and practice to an extent that you become a champion in it, no competition can ever affect you. Your personal growth and well being in life is guaranteed. Same with English. The key is to find the subject so interesting that you cannot help but master it, for these exams at the least. 

Is there a simpler way to crack these exams then? Is there a simpler way to learn English in a manner in which we are considered fit to be in a predmoinently English speaking country in the University where most classed will be in English, in an accent and method which is considerably different from that we have grown up with? I say the simpler way is to learn English in a manner which befits you joining the chosen University, rather than just cracking exams. When I take classes, and refer to a book written by a prominent author where the brilliant author teaches English grammer as a prelude to learning tricks of these exams, I tend to tell my students to remember there are such things as verbs and adjectives and adverbs, but focus more on the day to day usage where you use these automatically, rather than being conscious and thereby nervous, oh, I need to take my English lessons again? No, you don't need to, you just need to ensure you remember the way you write and speak and understand English, naturally, and that is all it takes to crack these exams and get the desired grades.  

Let's be blunt here, if you are looking to join an ivy league University which demands an IELTS of 8.5, then you probably would'nt be reading this blog anyway. You would not need any special prepatory classes, and giving the IELTS to get an 8.5 without batting your eylid those 150 minutes would be a breeze. You are here becuase you desire a band between 6 and 7 on the IELTS scale and are a bit worried that you might become nervous during the test, or you simply don't measure up to the desired band. Let me assure you, the fact that you are reading these paragraphs should be testimony that you worth at least those bands, if not more. Yes, taking some classes, either on the internet or in a school which provides these classes help, but the key is to ensure you can raise your confidence levels to recall everything which you have already read in life, from the first English class your teacher took at Kindergarden to the high school tests.