If there is no effort or work involved in losing weight, there is no incentive to keep the work you have achieved. 99% of people who take these jabs will gain it back as soon as they stop, but with the unknown side effects of these jabs on insulin/thyroid etc
There is effort involved, even with the drugs. They don't lose the weight for you. They rebalance things like insulin resistence and therefore, bring greater balance to leptin and ghrelin.
85% will gain it back. Not 99%. Still not great statistics but if your obesity is caused by hormonal inbalances then, yes, you need to keep taking the medication to keep those hormones in balance. Weight loss itself has long term (not great) effects on some of the hormones we are talking about. It's not as simple as 'you've done the work now just need to maintain it'. Sadly. But that's the same for lots of medications used to treat chronic problems.
I suspect the government is hoping to replicate the same impact the US has seen - in which obesity, for the first time in decades, is on the decline...