Hamilton has won a record-equalling seven drivers' championships, including six of the past seven with Mercedes.
Former team-mate Nico Rosberg won the title in 2016 when Hamilton faltered, meaning the Silver Arrows have accounted for seven straight triumphs, matching that streak in the constructors' championship.
Mercedes' advantage with a consistently excellent car is clear, as Stroll highlighted this season when he said: "If you put Lewis Hamilton in a McLaren, he won't win the race."
However, speaking to Stats Perform, the Aston Martin driver explained there is still no doubting Hamilton's ability.
Besides Rosberg's five-point 2016 triumph, the Briton has beaten his Mercedes team-mate in every season since he joined the team in 2013.
"You still have to beat your team-mate," Stroll told Stats Perform. "For example, in Mercedes, Lewis has Valtteri and he managed to win the title for so many years.
"You've still got to deliver every weekend and fight up in the front. He has been able to do that.
"But there is no doubt that having a good car makes the difference in the way you finish. This is the story of F1, that's how it has been for a long time and it still is."
Aston Martin, backed by Stroll's father Lawrence, earned only five points in the first four races in 2021 – none of them supplied by new signing Sebastian Vettel – following changes to car regulations that Hamilton has suggested were "done to peg [Mercedes] back".
Stroll, whose low-rake car uses a Mercedes power unit, said: "Last year, at the beginning, we were more competitive, but now, with new regulations, things are a bit different."
He does, however, enjoy being paired with four-time champion Vettel, adding: "It is great working with Seb.
"He is an incredible talent with great experience. He is a great team-mate I and look forward to working with him for the rest of the season."