I take it you didn't see the documentary on it where Spielberg said he didn't want to do it (he said Last Crusade was the final one and he intentionally had them ride off into a literal sunset). In the doc, he said Lucas and Harrison Ford kept badgering and calling him to do it. Spielberg finally relented. Can't go hard on a director when he wasn't feeling the script (blame Lucas for approving that script) but felt an obligation to two old friends and colleagues to go in one more time.

Also, Spielberg in the last 10 years has had Munich, War Horse, Lincoln, Bridge of Spies, The Post (two excellent movies nobody saw), and West Side Story all get nominated for Best Picture. 6 movies in 10 years - Tim Burton doesn't even have one BP nominated film. They are not the same.

Spielberg didn't write Indy 4 and it's issues largely come down to writing, it's still a pretty good,fun movie with a lot of exciting and memorable setpieces. Spielberg doesn't exclusively make great movies but he's not a guy who's anywhere near as indulgent as Tim Burton, or a guy who thinks every thought he has is gold.