Things were absolutely not meant to turn out this way!
The plan they devised and tried to railroad the Queen into accepting was for them to step down as FT working royals, cherry pick which events they did in future, 'collaborate' with the Queen on things that suited them, flit between the US and UK, maintain Frogmore Cottage as their UK residence, make money on the side from whatever speaking engagements and royal flummery nonsense they could get, while retaining their royal titles, patronages, Met Police security, and income from the Duchy of Cornwall. They could then have their cake and eat it - part-time royals with all the advantages and none of the disadvantages of royal life. No more walking behind W&K - they could just fly in, wave, wear the fancy clothes and jewels - and then fuck off again as soon as it was over.
Fully supporting themselves and having to pay for security was absolutely NOT part of the plan and a big part of why Harry is so furious and resentful now.