The Lakers have had a considerably easier schedule than the Spurs to this point. Even if some may want to quibble based on injuries, suspensions, etc. there is one undeniable result of the schedules to date; the remaining schedule for the Lakers is considerably more difficult than the one facing the Spurs. That guarantees nothing, but facts are facts.
Season to date records:
Lakers v above .500 teams: 5-5
Lakers v. below .500 teams: 26-7
Spurs v. above .500 teams: 15-5
Spurs v. below .500 teams: 20-1
Now one can write off some of the difference in winning percentages to various mitigating factors, but nothing changes the fact that the Spurs have played many more games against the better teams to date and, therefore, play many fewer games against the better teams in the second half.
Games remaining (+.500/-.500)
Lakers: 26/13 (including 5 against the bottom 7 teams)
Spurs: 18/23 (including 11 against the bottom 7 teams)