That's what guarantees that people will keep buying tickets as long as the odds are in their favor.
( That ( ( 's ( what ( guarantees ( that ( people ( will ( ( keep ( buying tickets ) ) ( ( as long ) ( as ( ( the odds ) ( are ( in ( their favor ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT That)) (VP (VBZ 's) (SBAR (WHNP (WP what)) (S (VP (VBZ guarantees) (SBAR (IN that) (S (NP (NNS people)) (VP (MD will) (VP (VB keep) (NP (NN buying) (NNS tickets)) (ADVP (ADVP (RB as) (RB long)) (SBAR (IN as) (S (NP (DT the) (NNS odds)) (VP (VBP are) (PP (IN in) (NP (PRP$ their) (NN favor))))))))))))))) (. .)))
People will continually purchase tickets, as long as they have a good chance of winning. 
( People ( ( will ( continually ( ( ( ( purchase tickets ) , ) ( as long ) ) ( as ( they ( have ( ( a ( good chance ) ) ( of winning ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS People)) (VP (MD will) (VP (ADVP (RB continually)) (VB purchase) (NP (NNS tickets)) (, ,) (ADVP (RB as) (RB long)) (SBAR (IN as) (S (NP (PRP they)) (VP (VBP have) (NP (NP (DT a) (JJ good) (NN chance)) (PP (IN of) (NP (VBG winning))))))))) (. .)))