I don't know if it's ruthlessness or he could just see (like a lot of us) that most of them were really not very good at the end of the day.
I dont know mate, its a lot of moving parts making up a whole of a dynamic, i think a lot of it is quite brave and ruthless.
I mean, Gomes, Dele are in our higher earner bracket, can imagine going to your boss and saying - you know these lads we drop 100k a week on - im going to bin them and want you to give me the guts 50 mill for two 21 years olds in Onana and Garner. Same at centre half with Coady and JT VS Mina (high earner) & Keane. Think it could have been very easy to maybe just stick with Allan or get another year out of Delph (on the back of the momentum at the end of the season) - i imagine it was also a hard sell, arguing shedding them for Idrissa.
Seamus, Keane, Doucoure are big profile players and good servants, also on big contracts, its a big call adding them to the best of the rest list, were they seem currently.
Its also the combination of all the above to the whole, every single decision in isolation in a way is logical like you say but many together absolutely change the whole dynamic, identity and maybe culture. Its wrong footing the whole squad, when previous sure fire players in the team are now maybes, it conveys there is a standard and all needs to be earned and continuously proven, a competitive healthy tension.
Think there is definitely a ruthless streak in Lampard.