Hamilton, 37, won six of the seven titles leading into the 2021 season, but he appears incapable of getting back to the mountain top just now, with Mercedes so much slower than Ferrari and Red Bull.
Alonso, 40, won back-to-back championships in 2005 and 2006 with Renault, and after a strong run with Ferrari in the early 2010s, he struggled mightily after his move to McLaren, finishing 17th, 10th, 15th and 11th from 2015 to 2018.
After trying his hand at other racing disciplines in 2019 and 2020, Alonso returned to F1® with Alpine in 2021, where he is now partnered with Esteban Ocon as the two battle it out in the midfield with a car that cannot compete for wins.
Speaking to BBC Sport ahead of the Spanish Grand Prix, Alonso highlighted how often the success of a driver can be out of their hands, and expressed only limited sympathy for Hamilton's struggles this season.
"This is the nature of the sport," Alonso said. "Sometimes you have a better car, sometimes you have not such a good car and you still need to fight and make some progress.
"This year we see that the driver is very important in F1, but not crucial. Lewis is driving as good as he has been the last eight years. He was dominating the sport and breaking all the records and 100-and-something pole positions.
"Now he is doing a mega lap – as he said in Australia or somewhere like that – and he is one second behind. So, yeah – welcome."
Alonso compared his championship years to Hamilton's, saying often the true stars of the team are behind the scenes, while the drivers get to soak in all the glory.
"To have more than 100 pole positions in F1 is something unthinkable. You need to have the best car and package for many, many years," Alonso said.
"He deserves everything he's achieved in the past, but this year is a good reminder that in all those records and numbers, there is a big part on what you have in your hands as a package in the car."
In a show of respect for this generation's most successful driver, Alonso predicted Hamilton will rebound from a slow start and finish ahead of team-mate George Russell this season.
"George has been very fast in the last few years and I think everyone was expecting him to be a tough competitor for Lewis," Alonso said. "But I still believe Lewis will eventually finish the championship in front.
"This is just a five-race championship [so far], but eventually when things are more tricky or [there are] difficult situations, Lewis will still have more experience and maybe more talent."