Hard to imagine how one might need more than 128 unique plug-ins in a DAW session, but its true, in some complex productions and scores they do ad up. In a new update for Windows 10 (build 18312) preview - soon to be released. There have been modifications to the Kernel code allowing for an increase in the number of FLS slots - this is the term for the way that Windows handles the Threads or "Fibers" - these are lightweight threads used by C++ code snippets - the language that most VST plugins are written in.
The current limit of 128 may sound high, but actually the DAW itself may well use 40 or more of these FLS slots to start with. The new Windows 10 build 18312 which is currently in preview, allows for just over 4000 FLS slots - that should do it.
More importantly, as we see ever more powerful CPU and increased memory and storage this will mean that Windows 10 will let us take advantage of that capacity.
The Windows 10 update is slated for the 19H1 release - which in Microsoft internal speak means "the first half of 2019". Microsoft do have a program for people who want to test:
Highly technical users who have hit this limit and want to test can use the Insider build on a non-critical PC to test it out. They'll need to join the Insider program to do so.
But for the rest of us, the release will be out in the next few months.
For more details of this and other features in this update, check the Windows Blog