For most ordinary folks it might indeed be a positive. However the people in charge of a country's finances see it in a completely different way. Picking one issue in the news recently both here in the UK and the USA, older populations impose heavier loads on health infrastructure and the like, money must be found from somewhere. The USA has the easiest political solution: people must insure or pay. The UK though, we're not so lucky as to let people die because they can't afford healthcare, the ordinary taxpayer pays.

The UK's financial model relied, pre-Brexit, on an extra 1.1 million people paying tax by 2020 to simply stick at current spending levels, admittedly across every infrastructure demand this country faces.

Immigration FTW!!!2!ยก ;)