If we want to find the best shooters in basketball history one method is to simply look at players with the highest shooting percentages. Here is the table from Basketball-Reference showing the Top 100 Seasons in NBA History by True Shooting Percentage.
The chart above would lead us to believe that more great shooters played in the 1980's (orange) than any other time in basketball history. Whatever the reason for the big jump in shooting efficiency (introduction of the 3-point line, less emphasis on defense or legitimately sharper shooters) doesn't matter when evaluating performance across era's.
The fact that players from one decade plus 1995 & '96 (shorter 3-point line) dominate the list of most efficient shooters means we need to adjust performance to account for the playing environment. Comparing shooting percentage's to league average allows us to make more complete evaluations of players in the pre-three point line era and the decade following 1996.
A metric like True Shooting+ gives us a more accurate picture of shooting value across time periods. Now good shooters who played with guys who threw up a ton of bricks move up the list of all-time greats.