Harry Kane is considered to be one of the best strikers, in the Premier League. The 6 ft 2-inch tall striker has become the first player in the history of Tottenham, to score 20+ goals for five consecutive seasons. In the current season, he is the joint highest goal-scorer alongside Mohamed Salah and Pierre-Emerick Aubameyang, with 14 goals.
In the last season, he bagged an astonishing 41 goals in 50 games, in all competitions. For Tottenham, Harry Kane has scored 122 goals in 175 league matches, so far.
Aguero is another lethal striker who scored his 200th goal for Manchester City in August 2018. In the current season, he has netted 10 goals in just 17 matches. Nowadays, he is struggling a bit with fitness as he has already missed 5 league games. So far, Sergio Aguero has scored 153 goals in 223 league games for Manchester City.
The reason why Harry Kane is not on the same level as Sergio Aguero is his goal-scoring ability against the top clubs. He is often found missing in the crucial games and his record against the top 4 clubs in the league, is an example. In the current season, he has scored only 3 goals including a penalty, in 7 games against the big 4 clubs in the league. On the other hand, Sergio Aguero has scored 2 in 5 matches, against the top 4 clubs while playing only 380 minutes.
So, the goal per minute ratio for Kane and Aguero is 210 minutes/goal and 190 minutes/goal respectively. The story remains the same while comparing the stats of previous seasons.
Another reason is the effectiveness of his goals in comparison to the goals scored by Aguero. Whenever Harry Kane has put his name in the score sheet, he has often scored 2 or more goals. Many of his hat-tricks have been scored against the mid-table Premier League clubs. They wouldn't have much impact on the results, if he had scored only 1 goal, instead of 2-3 goals. So, most of his goals have not turned out to be the match winners.
On the contrary, Sergio Aguero has always been a threat in front of the goalpost and has recently scored his sixth consecutive goal, in as many matches against Liverpool. It's hard to forget his last minute goal against Queens Park Rangers in 2012 which was the title-winning goal for Manchester City.
So, Harry Kane still has a long way to go, to become as prolific as Sergio Aguero.