Intel made one single bad bet - their 10 nm process didn't work as well as they expected - and TSMC, who made the right bet, leapfrogged them.

In terms of architecture and vulnerabilities, it's not prudent to bet Intel chips are more vulnerable to exploits than others - it's just that we know more about those vulnerabilities. If you want to find vulnerabilities with high impact in cloud and enterprise data centers, Intel Xeon CPUs will be your primary research target.