A company with a $100b market cap seems unlikely to build or lease a supertall building. Public companies generally don't go for vanity projects.
Philly's and San Francisco's new HQ towers follow these rules...supertalls make sense on spreadsheets in those places, when tenants place huge value in being in the absolute core districts, right next to transit. They can also do very low parking ratios...the latest Comcast
tower has 77 spaces for I'd guess 7,500 workers.
Less parking avoids a big cost for any job, but this is more important with a bigger tower...either you need more land for parking on the side, or you have a huge amount of tower structure, transportation, etc. competing for space in your garage, particularly if the garage is above-grade.