Where could Tame Impala go after achieving the rare synthesis of indie appreciation and mainstream success following their 2015 album “Currents”? There is a wide spectrum of possibility for the follow-up to a big hit in today’s fractured, ultra-competitive music climate. On one end, artists can reinvent themselves completely and suffer financially for it. The public wanted Arctic Monkeys to release another “AM,” but frontman Alex Turner instead gave them the Bowie-esque “Tranquility Base Hotel & Casino,” a concept album about a moon resort with good tacos. Conversely, artists can put up a facade of change that is broadly palatable but lacks personality or purpose. Justin Bieber’s “Changes” carries big messages of transformation but fails to take artistic risks. This dilemma — forgoing commercial success for niche left turns versus talking about musical evolution without actually delivering the goods — belies an inescapable truth of art: Change is hard.