Apples and oranges, Delphi != C++, and on top of that I don't think you really want to make the argument that the Delphi IDE can do all the things CLion can do for C++. I fondly remember my time writing Delphi, but I'm not jaded enough about the resource requirements of modern IDE's to pretend that you can compare these environments equally.
Anyway, I don't really see the point you trying to argue here. It appears you are principally opposed to software that uses more resources than what you consider necessary, which is fine and in the case of something like CLion or VS code justified to some extent, because they are far from lightweight. But if you remove these ideological objections from the discussion, none of this actually matters all that much considering typical workstation hardware. I honestly don't mind trading 4 or 8 of the 16 GB of RAM in my laptop for all the features I get from CLion compared to the alternatives. A full compile and run of the thing I'm building can easily get by with (much) less than 2 GB. And if I would be developing something that uses up 8+ GB by itself, I probably want a beefier workstation with 32 GB or more anyway. It's just not an issue, RAM is plentiful, and it's in there to be used.
All my laptops have 32GB of RAM. And if I had no other options I probably could've been stuck with CLion. However as I've already mention CodeLite and QtCreator are multiplatform, very responsive, work just fine as an IDE and eat very little memory comparatively to CLion. I often have to test big in memory datasets so I have way better ways of wasting RAM.
Anyway, I don't really see the point you trying to argue here. It appears you are principally opposed to software that uses more resources than what you consider necessary, which is fine and in the case of something like CLion or VS code justified to some extent, because they are far from lightweight. But if you remove these ideological objections from the discussion, none of this actually matters all that much considering typical workstation hardware. I honestly don't mind trading 4 or 8 of the 16 GB of RAM in my laptop for all the features I get from CLion compared to the alternatives. A full compile and run of the thing I'm building can easily get by with (much) less than 2 GB. And if I would be developing something that uses up 8+ GB by itself, I probably want a beefier workstation with 32 GB or more anyway. It's just not an issue, RAM is plentiful, and it's in there to be used.