this is absolutely incorrect.
confidence comes from the backing of good management.  when you are certain that the system is in place on merit and that you will get the opportunities you deserve, you are able to utilize your talent in the way in which your strengths come to the forefront.
the correct reason why they bat like scared kittens is because they know that one mistake and they may never play again, regardless of their first class performances.  
ask fawad alam
		
		
	 
When you are not good enough, backing from the management will not make you a top player, and when you are good enough, you will make your opportunities count anyway. 
Besides, this whole backing stuff has become a convenient excuse for our fans to defend their favorite players. 
If they do well it is because of how talented they are, but if they do not do well it is because the management did not give them confidence. 
Pant is a prime example of why it is not about backing only. 
Pant is always shafted for Saha when it comes to home Tests, he was not picked for the first Test in spite of his blistering hundred in the practice game, and yet, he has grabbed his opportunities and continues to do so whenever he is given the chance in venues like Australia and England. 
He is incredibility talented and he knows it, which is why he plays with supreme confidence even though the management was not fully convinced over his place in the team. 
Instead of struggling with lack of confidence because he did not have full backing of the management, he has instead forced the management to have confidence in him. 
I am not saying backing does not help, but it is not the difference between success and failure. A truly talented player will force the management to back him with his performances. 
We can extend this to Gill as well. He was not picked ahead of Shaw for the first Test and Rohit was flying over from India as well. He made his debut against an elite level attack when India were 1-0 down in the series. 
A failure or two would have meant that he would be out of the playing XI and will then have to work his way back into the team. However, because he is extremely good, he had the belief that he can grasp the opportunity and convince the management that they should not look elsewhere. 
Does Siraj have backing? No he doesn’t, he wasn’t first-choice and probably will not be first-choice when Bumrah, Shami and Ishant are fit, and yet, he grabbed his opportunities. 
Fawad Alam is averaging mid 20s after his comeback. If at the age of 35 after 12,000 FC runs and 160+ matches, he is averaging mid 20s, we cannot blame the management for not giving him confidence. It exposes flaws in his batting technique and method, which is why he has got out to a quite a few tame deliveries. 
Adam Voges was picked at the same age by Australia after he scored mountains of runs in Shield cricket, and he averaged 60+ in Test cricket. 
There was no talk of Naseem Shah getting axed until now and what did he do? He failed in Australia he was backed by the management. That led to his failure in England. 
He was still backed by the management and that led to his failure in New Zealand. Now that he has been rightly dropped, how is it fair to blame the management for not giving him confidence? The reality is that he is just not good. 
Shan Masood has had plenty of backing throughout his career and especially in the last 3 years, and he is still awful.