He was considered top 10 by many people at the end of last season. He may not have won the popularity contest for DPOY but he was the top rim protector in the NBA by a long shot and either 1a or 1b of the most impactful player on the defensive side last year. Defense is half the game. He was #1 in blocks per game, total blocks, #2 FG%, #1 TS%, #1 Block %, #1 Defensive Win Shares, 2nd team all NBA (10 players on that list), 1st team all defense, #3 defensive rating, #3 offensive rating, #2 win Shares overall, #3 defensive box score +/-, #5 rebound %, #5 offensive rebound %, #4 rebounds per game, #4 total rebounds, #20 PER, #15 value added, #15 estimated wins added, #1 net rating per possession, #8 Value over replacement player, #15 in Box +/-, #8 WS per 48, #10 offensive win shares and many more top stats that easily put him in the top 10 based on stats alone and no personal opinions.
Last season (especially towards the end of the year) Gobert was top 10 or awfully close. If you look at these stats for the last couple months of the season he is much higher ranked as well in comparison.
http://uproxx.com/dimemag/jazz-rudy-gobert-gordon-hayward-build-defense/3/