Leicester sold some of their best players after winning the premier league back then and it was more for money and the thoughts of, retraining others to replace those sold and rebuilding from there, hence why they never stand a chance till date.
The best move has always been to buy top performance players from same league or from one that plays similar style of football, not to buy from a different league and hope the player catches on fast and delivers on the pitch.
For wenger then, he believes in training players and nurturing them until they are great and then sells them. His ideology was more of a manager and business man as compared to the ideals of Mikel Arteta who is more of a coach than a manager. He understands that what it means to buy young, hungry and talented players like he did when he got Rice, and Martinelli and well it was a good coaching decision which has helped his career excel so far.
When looking at Leicester's actual condition since they won until they were relegated they were always fine because they always had the status of a dark horse club in the EPL but their problem was the financial condition which was very disturbing especially when Covid attacked and the peak last season when Brendan Rodgers could not do what he planned when he wanted to sell some players he did not need in future plans and could not buy new players to support his plans which made Leicester run out of steam and actually plunged into the relegation zone in just one season.
In the end, in this case we see something where finances are important so that every club that is really serious about maintaining their condition and performance must realize that finances are necessary to support their future stability.