You could say the same for law, its to keep lawyers employed. I suspect the rules are rules on top of rules, with unintended consequences, resulting in changes to rules.
Capping pensions probably made sense to avoid lost tax revenue, but the consequences will be more people with their hand out for state benefits when they retire.
2nd property tax, impacted the housing market as those with more than 1 house were stuck in their home due to the extra fees.
Increases in corporation tax results in HQs moving elsewhere, increases in income tax results in off-shore earning. EU tax harmonisation allows rich countries to "steel" tax from poor countries.
One countries tax incentive is another's tax haven.