They are both decent platforms. Do what pros do - pick your SW including OS first and then choose the best platform to run it on. Macs have the advantage of simplicity of operation, especially appealing to those with less than stellar computer skills. They also have nice inter platform data sharing - Mac to IPad to IPhone. The downside is cost/performance and the lack of upgradability. PCs are substantially less expensive for the same performance or provide higher performance for the same $, much easier to upgrade and allow a skilled user to work “closer to the machine” (by that I mean you have closer access to the inner workings of the HW and OS).

Regarding Windows OS vs Mac OS, historically both have a similar number of patches/upgrades. Ther are more viruses aimed at PCs because PCs comprise >80% of al personal computers sold (there are reasons for that). Macs have viruses also, but the fact is that computer security is typically compromised by user errors and bad computing practices, not the vulnerability of the platform.

Yes, you can keep a Mac (or a PC) for 10 or more years, but at the expense of lousy performance as SW/OS complexity continues to evolve. Computers are not an investment any more than meat is if you have no refrigeration - they are a depreciating expense that eventually become worthless.