That is according to former Blues captain John Terry.
The trio are all excelling at their respective clubs after leaving west London while Jose Mourinho was in charge.
Salah has netted 20 times in all competitions this season, De Bruyne has been instrumental in Man City opening up an 11-point lead at the top of the Premier League, and Lukaku is back playing under Mourinho, after the Portuguese boss splashed out £75m on him.
However, when asked if Chelsea should have regrets over losing the three stars, Terry told Sky Sports: "Not really, because at the time they didn’t make our team stronger.
"Let’s not forget we were one of the best teams probably the Premier League has ever seen, in them early days when they arrived.
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“Let’s not forget we were one of the best teams probably the Premier League has ever seen, in them early days when they arrived”
Chelsea legend John Terry
"So they was coming into one of the best sides which was even more difficult.
"When they come in can they make a big enough impact to sustain and keep their place?
"No, it’s very difficult to do."
And the Aston Villa player went on to admit it was hard for players to find their feet at Stamford Bridge.
Especially the youngsters.
"That’s why I think, even at Chelsea, you look at [Andreas] Christensen he’s come in and done great, keeps his place.
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"David Luiz is now out and fighting for his place.
"When you’re a younger player like [Ruben] Loftus-Cheek coming in, can you set the world alight in a cup game or whatever game you’ve been given? The last group game of the Champions League?
"I don’t think that’s enough for these boys to go “that’s enough game time to show I’m a Chelsea player”.
"I think unfortunately he then has to go away to a Crystal Palace. For me he’s good enough to come back to Chelsea.
"But sometimes you have to go away. I done it when I was younger."
Chelsea take on Bournemouth tomorrow evening (7.45pm).