People haven't stopped beta testing. Either in hardware or software. They have been quicker to release because the vast majority of software nowadays are done inside a sandbox (mobile apps, cloud servers, etc) rather than from scratch.
It's not like software or hardware back then was any more reliable. Office, OS9, Windows (all versions) have always been plagued with problems and one can argue they have fewer obvious bugs now than they did before - When's the last time you got a BSOD?
The counterbalance is that the consumer base is far far far larger now. Some of us who were at Intel at the height of the Pentium 4 were happy to have sold 40M units in a year. Mobile phone processors at qualcomm nowadays clear 400M/quarter.
If it seems like hardware and software bugs show up faster, it is because the userbase that uses and report such bugs (easy to do now via social media) is much much much larger.