If the batteries are so expensive they can't have a proper interior it is odd that Tesla ships some models with extra battery capacity for future purchase optio

If the batteries are so expensive they can't have a proper interior it is odd that Tesla ships some models with extra battery capacity for future purchase options: http://www.theverge.com/2016/5/5/11597508/tesla-model-s-70-battery-upgrade-pay-unlock-battery http://www.theverge.com/2016/5/5/11597508/tesla-model-s-70-b... I think the interior is shit because it's hard to do at scale and Tesla hasn't been doing it for very long.