Sanju is middle order batter and WK. For the middle order WK spot, his competition would be KL Rahul. Even if we look at Sanju as a pure batsman then still SKY (so far he failed but he's clutch player) and Iyer(if fit) are there to give him competition. Overall big headache for the selectors.
And you are forgetting the fact that Rishabh Pant will be fit again in a few months. At this point, everyone else mentioned in the above post have shown more consistency when compared to Samson. I am glad that Samson finally got a fifty, but I don't know whether he will be able to perform like this against strong teams like Australia and England. His style of batting is not very suitable against these teams. Even Venkatesh Iyer is more preferable comparable to Samson. That said, there is nothing wrong in Samson getting a few more opportunities.
Regarding his consistency.