We're not getting OS19 but OS26. Rumor has it that it will still support the latest generation of Intel MacBook Pro and Intel iMac and iMac Pro. If true that means OPLC will continue after Sequoia.

macOS Tahoe could drop support for some older Macs, including the 2018 MacBook Pro, the 2019 iMac, the 2017 ‌iMac‌ Pro, the 2018 Mac mini, and the 2020 Intel-based MacBook Air. The update is expected to be compatible with the following Macs:

• ‌MacBook Pro‌ (2019 and later)
• ‌iMac‌ (2020 and later)
• Mac Pro (2019 and later)
• ‌Mac mini‌ (M1 and later)
• Mac Studio (all models)
• ‌MacBook Air‌ (‌M1‌ and later)