It all comes down to the 80-20 rule and how production size and budget scale:
You would need 8 times the resources you spend to complete 80% of your project to finish the last 20%.
So there always will be space for some improvements though the resources time and money are limited and thereby setting the frame for the production.
And I think reaching 80%, sometimes even 85% or 90% with that tiny resources and an amateur team is a great achievement.