You can win from scoring lots of goals, or you can win from conceding very few goals. Generally speaking, SAF was definitely in favour of the score lots of goals mentality, which is absolutely my favoured strategy too, and a big reason why I liked Ole - he favoured attack over defence. The big, absolute key is goal difference. In only one season did SAF not have a goal difference higher than 42 and not win the league (97-98), and of all his title-winning seasons, only once did he have a goal difference below 38 (96-97).
Since he left, only Jose has managed a goal difference higher than 30 in a season, when we had a goal difference of 40 and finished 2nd (17-18).
In title-winning seasons, our lowest goals for was that of 68 goals in 08-09, when we managed to keep a high goal difference due to conceding only 24 goals, a feat only achieved and bettered once before (22 goals conceded the previous season, 07-08).
In title-winning seasons, our highest goals against was that of 45 goals in 99-00, when we managed to keep a high goal difference due to scoring a whopping 97 goals, our highest ever tally in 38 game seasons.
So, I feel it's relatively safe to say that our bare minimum requirements for getting 1st would be to concede fewer than 45 goals and score more than 68 goals. Until we can manage both of these, unless we intend to break SAF-era records, we need to both score more AND concede fewer goals. We've scored 68 or more twice, and conceded 45 or fewer 8 times.
In the 10 seasons since SAF left, we have managed to score more than our average goals scored in title-winning seasons (79) on zero occasions, and concede fewer than our average goals conceded in title-winning seasons (34) on two occasions.
So yeah, probably scoring more is the bigger concern overall, but we definitely need to do better in both areas if we want to contend.
Stats below for those who like 'em.