Interesting post. Larsen was certainly remarkable with his consistency and a lynchpin of the successful NZ ODI team for a decade.
No doubt he would struggle more today with the bigger, lighter bats and batsmen becoming more inventive with T20. I remember Chris Harris was hugely economical with his little leg cutters through the mid 90's, but batsmen also started targeting him and he was less effective in the early 00's.
James Franklin has been reasonably effective this season bowling around Larsen's pace, but with a number of variations. Larsen was such a competitor I imagine he would have adapted to some extent.