As long as the player is no longer in peak physical shape, as you said, from the age of 25-27, in my opinion, it's not so simple to define whether you're old enough to play soccer
If the team has a good composition of young players and older and more experienced players, it can use the experience of a player of this size to its advantage. A player who has played in Europe, Champions League, against all the best teams in the world, the World Cup, etc., has a lot to add to a team
I didn't know peak performance for soccer players was 25-27
I've heard that usually peak performance for men is 33 but you can probably mitigate age related issues by training, sleeping and eating well, with some limitation, of course, as an example it'll be hard to see a 50 years old compete with a 25 who's in shape and practicing often.
33 is a peak for a regular men. Professional athletes have their peak lower (for example at artistic gymnastics athletes professional athletes retire at 17-19y.o), because they always put their body on the limit, their body exhaust more. If they were machines, then they have huge mileage. Like taxi cars breaks or die faster than regular cars Why football players retire early - probably due to muscles structure, flexibility, body recovery phases and etc.
Look at the players who played during 90's for example, most of them retired before 35, and look at now, most players still play after 35 as well. This means that we need to realize that Suarez is still good enough, and I think it should be noted that he has been playing well right now as well, maybe he is not at his peak I can see that but he is still playing very well and still gets a lot of attention as well.