It is vital we are able to continue to attract these scarce skills from a small but significant group of high earners, and retain those we have.It may, indeed, be "vital" to attract, and retain, "scarce skills" but has it really been proven that only "high earners" have those skills? Are the "skills" scarce or are they just scarce among high earners. If they are scarce among high earners has a search been done to see if, perhaps, they are common among low to middle earners?
Is there any grounds to the accepted wisdom that high earning people must have loads of skills, loads of scarce skills otherwise why would they be high earners? It is time to crash that shibboleth. Many "high earners" became so because of luck, being in the right place, cultivating a personal network and not because of any important "scarce skills", (those skills described may be "scarce" but are they worth paying a premium for?).
Being a "high earner" does not mean you have "scarce skills" (after all a skill can be taught). You could rise through an organisation through "favouritism" and be seen as a successfull achiever through the efforts and talents of other people. Now that would make you a "high earner" with no skill.
Is someone earning over three times the national average wage really contributing three times more than someone on the national average wage? Are they working three times harder? Three times longer? Three times smarter? If they are not making three times the contribution is not their remuneration just theft from the company owners?
White's suggestion of "separate pension schemes for ... executives" is just saying that the Civil Service needs bigger thieves.