I dont think a perjury charge would stick.
But time will tell.
Making something stick is not the point. In fact, it would just be icing on the cake.
The point is to do everything possible, be it moral, legal, ethical or not, to hamper Trump's ability to get things done and especially to prevent him from doing anything that might be construed as successful. Thus, the goal is to tie him up with endless hyperventilating faux outrage at anything that can be twisted to look scandalous and leave the country in misery to hamper his chances at re-election. Winning is all that matters, and Sessions is just the target of the day. Remove him and they'll look for someone else.
The difference now is, Trump is not afraid to get in the mud like previous Republicans. It will be interesting.