Nvidia is $3.42T market cap. AMD is $246B market cap. Nvidia makes up over 5% of the ETF I use. AMD is less than 0.5%

There's a lot more wealth tied up in Nvidia, so there is more interest and worry. They are also more associated with hyped up tech like Bitcoin and AI. Whether you believe in those technologies in the long term determines whether you're likely to think Nvidia can maintain.

With everyone dumping on Intel lately, AMD also looks like the primary CPU manufacturer.