Daihatsu are a far better company than attempt to do that to them.

They have innovation and originality in their history.

Daihatsu is Japan's oldest car manufacturer - founded in 1907, 30 years before Toyota - and they were also the first Japanese car manufacturer to export cars to the UK. So they have a lot of heritage and wouldn't deserve to be Toyota's budget brand.

They co-develop a lot of models with Toyota (for example the original Yaris), and in other markets there are quite a few Daihatsu models re-branded and sold as Toyotas.

Perhaps if Toyota had been responsible for importing Daihatsus into Europe , as in the US, rather than having separate arrangements, and if more Daihatsus had been exported from their Indonesian plant, rather than Japan, the viability and exchange rate issues wouldn't have been so overwhelming.