Reason - why one ui 7 updates are late in previous generation devices like ,a55,m55,m15 , f55, f15or old devices
Samsung invested lot of resources in ui 7 so while launching new models they kept new device hardware with very less upgrade and depended all in new one ui7
Now if they provide one ui7 to previous generation device Now, people will prefer these devices only instead of new as there is very less hardware upgrade but cost is less as compre to new devices
They want people to buy new devices so profit will be more
