There's infinite things to do in many software companies. You're only given 40 hours of work per week. If you had the stamina for two jobs, then they'd give you 80 hours, with more than double the pay. That's what factories and gig jobs do.

But everyone believes that 40 hours is the peak, maybe less, before efficiency drops. You need rest to do well.

If you can perform, then just get a better position or a better job. Take on more responsibilities. Use the spare time to fix the problems that nobody brings up. If you can't, then chances are you're not really performing. If you are performing, why aren't you in a CxO position? If you are in a CxO position, are you hitting the 10% week on week growth benchmark?

I feel that most people doing two jobs are really just taking multiple low positions with low expectations and low salary caps. It's not always laziness, sometimes just market inefficiency.

Now if you are one of the people who can do multiple jobs effectively, consider consulting, where it's completely fine.