Will smaller companies have the budget to train the models, and pay the ML researchers to build and develop them?
Estimates say it cost millions to train those models (https://www.reddit.com/r/MachineLearning/comments/hwfjej/d_the_cost_of_training_gpt3/) and OpenAI in particular have been pretty clear that they see scaling models up as the best path to better performance (like this https://lastweekin.ai/p/the-ai-scaling-hypothesis).
And in reality, you don't just train one model, there will have been many, many iterations to get where they are.
Will a startup have the financial grunt and / or the in house computational resource to catchup to the big players? They'd need a lot of resources from somewhere.