It can… however I’ve met hundreds of monks whose whole existence is aimed at Jhanna practice - for decades, full time - and they’re not able to reach the first Jhanna.   If you can do it in 3 years then you’re either a ‘stream enterer’ from a past life or are exceptionally gifted both in terms of meditative ability and the life circumstances that afford you a genuine teacher willing to teach you and the ability to cultivate full time. A very rare occurrence…   An 80-something yr old abbot in Burma told me he’s only seen one such person in all his life. (And he’s taught thousands of people)   Then again he’s had several disciples that have managed to achieve a few of the Jhannas by simple dedication.   This is all to say that the Jhannas are (by some) considered the very pinnacle of meditative attainment. 
  Getting there in 3 years as a lay practitioner is almost unheard of.
  You need a teacher that is able to do it… you need to live in a retreat style setting with that teacher (even the normal monastic setting is not conducive)… You need to have a range of existing talents and qualities… Then you have a small chance of achieving it by the end of your life.
 
If you’re able to achieve Jhanna without it, then overt energy work is redundant for you. 
The alchemical approach to achieving practically the same thing as Jhanna works differently. The underlying mechanics are altered in your favour.
That’s how it increases the chances of achievement. It makes it possible (though still improbable) if you’re not already a stream enterer - and it makes it possible for people who lead a ‘normal’ life in society (though lengthy retreat and a genuine teacher are both still necessary).
    • Like
    3