With 'Better images' people often mean today less noise and higher dynamic range.
While this is true, the returns are diminishing.
10y ago a 35mm sensor was 1 stop better than APSC, today a 35mm sensor is 1 stop better than APSC [1]. The difference is that 10y ago an APSC sensor was usable at 800 iso and 35mm at 1600iso, while today an APSC sensor is usable at 6400iso and 35mm at 12800iso. The usable range today for the smaller sensor is 7 stops (starting at iso 100) and 35mm is 8 stops, while it was 4 stops and 5 stops 10y ago. 35mm will always be 1 stop better for the same generation [2], but the increase of 1 stop in relation to the usable range (1/5 vs. 1/8) is going down. Same for dynamic range.
[1] Due to 35mm sensor being double the size of APSC and iso being log2
[2] And manufacturer