For international? Yes absolutely. And until there is a vaccine I would assume the number of people travelling without insurance would be even lower. Let's say someone has booked their European holiday and at check-in when their temperature is taken it registers they have a fever. They are sent for testing and it turns out they have Covid-19 and can't travel. No insurance so they lose flights/hotels/excursion etc etc. How many people do you think are going to chance that when they can book a domestic/driving holiday with far less risk? I could also foresee a situation where poorer countries will not let tourists enter without medical insurance in case they develop Covid-19 and require hospitalisation.

As lhrsfo points out the cost of insuring that risk will probs make it prohibitevley expensive for 95% of travellers.