Mac hardware lasts longer than their software -- Apple is fairly aggressive about dropping support for older machines. Still, 8 years is a good run. Software developers who want to use the latest features have to use the latest Apple Software Developers Kit (SDK), and if Apple drops support for older hardware, the developer has to choose between using an out of date, unsupported SDK, or using the new SDK and leaving some users behind.
As noted, your 2024 tax data file can be imported into Turbotax 2025 for Windows 11. However, you can't open, change or print your 2024 (or older) data files without having the Windows 2024, 2023, 2022 etc versions installed as well (at substantial cost). The 2025 program can't open and print a 2024 return, it can only import from it to start your 2025 return. So if you are dropping the Mac, you should print or save PDFs of all your old tax returns.
You can also switch to Turbotax online, you can upload your 2024 tax data file into the "cloud" to use Turbotax online. TT online will work on older computers as long as the web browser is up to date.
