Why did SARS not spread to the same extent as COVID -19?

Hi

Why did SARS (2003) not spread to the same extent as COVID-19 has been doing? It seems to me that Chinese tourism wasn’t what it is today and would have limited its worldwide reach. Was it the DNA vaccine for SARS that prevented its spread? What were the reasons
I look forward to your feedback

It seems from my reading that it comes down to the degree of infectiousness. The original SARS was not as infectious as COVID-19.

There is no vaccine for SARS. Clinical isolation and quarantine remain the most effective means to prevent the spread of SARS. Other preventive measures include:

Hand-washing
Disinfection of surfaces for fomites
Avoiding contact with bodily fluids
Washing the personal items of someone with SARS in hot, soapy water (eating utensils, dishes, bedding, etc.)[8]
Keeping children with symptoms home from school
Simple hygiene measures
Isolating oneself as much as possible to minimize the chances of transmission of the virus

FYI, SARS has a much smaller latency period and unlike COVID19 it’s not infectious unless a person is showing symptoms. It’s a hell lot less infectious.