You might be thinking more about eFG% than TS%. TS generally more evens out the efficiencies from shooting only at the hoop (all-time leader DeAndre Jordan), racking up FT's you're automatic at (Adrian Dantley), bombing in threes (Reggie Miller), doing purely the latter two (Chauncey Billups), for example. Stephen Curry is the only guy in the top seven NBA leaders in TS to take more than 40 three point attempts in their whole career. Reggie Miller is next, then it's Chuck and then Durant.
LeBron's career 58.6% TS vs. Jordan's career 56.9% isn't purely from threes, LeBron has surpassed Jordan in general FG% too now. Where LeBron most benefits off threes is that his superior three point making (Jordan never was a good three point shooter when the line was longer except for short periods) makes up for his inferior FT%.
Since LeBron went to Miami and came back, his FG% is 53.4%. Taking Jordan's seven best seasons, his FG% is 51.8%. LeBron's taken and made twice as many threes at 36% vs. Jordan over those years hitting 35% (most of which come from two seasons, one of which, plus his 17 game comeback, being at the shorter line) but that generally evens out the fact that LeBron has taken one less FT a game while making two fewer since he shot 74% vs. Jordan's 84%. It's the FG% that separates them more now.
Where TS% probably most underrates is players who didn't even have the three point line. It also really hurts their points. I saw a blog post where someone gave Jerry West, Pete Maravich and Rick Barry hypothetical 3PT shots that weren't even like Miller/Allen/etc. levels and it could add up to five points a game to their averages. Not to mention anecdotal evidence about how often they shot from out there but only got two points for it.
Even without it, the relative performance of some of those guys was pretty impressive even if they never could hit the 60% range without, Big O:
1960-61 NBA .555 (1st)
1961-62 NBA .554 (2nd)
1962-63 NBA .588 (2nd)
1963-64 NBA .576 (2nd)
1964-65 NBA .561 (3rd)
1965-66 NBA .563 (2nd)
1966-67 NBA .583 (2nd)
1967-68 NBA .588 (2nd)
1968-69 NBA .579 (2nd)
1969-70 NBA .577 (3rd)
1970-71 NBA .563 (7th)
West:
1961-62 NBA .524 (8th)
1963-64 NBA .561 (4th)
1964-65 NBA .572 (2nd)
1965-66 NBA .573 (1st)
1966-67 NBA .559 (4th)
1967-68 NBA .590 (1st)
1968-69 NBA .557 (6th)
1969-70 NBA .572 (6th)
1970-71 NBA .571 (5th)
Rick Barry has the advantage of the seasons he played in the ABA giving us a peak at the possibilities even though he took 1.5 a game at 28%:
1968-69 ABA .616 (1st)
1969-70 ABA .582 (1st)
At 35, his final season, he took 3 a game and hit 33% in the NBA's first season with the line.
for comparison, LeBron and Jordan and Curry:
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2011-12 NBA .605 (9th)
2012-13 NBA .640 (3rd)
2013-14 NBA .649 (2nd)
Active .586 (10th)
Career NBA .586 (37th)
1988-89 NBA .614 (6th)
Career NBA .569 (88th)
2013-14 NBA .610 (6th)
2014-15 NBA .638 (4th)
2015-16 NBA .669 (1st)
2016-17 NBA .624 (10th)
2017-18 NBA .675 (1st)
Active .621 (3rd)
Career NBA .621 (5th)
Tyson Chandler:
2006-07 NBA .620 (4th)
2007-08 NBA .632 (5th)
2010-11 NBA .697 (1st)
2011-12 NBA .708 (1st)
2012-13 NBA .671 (1st)
2014-15 NBA .697 (2nd)
Active .625 (2nd)
Career NBA .625 (4th)