This is not happening though... The opposite is - vendors hiring people that would otherwise make 0 contributions to Istio and now are. 4 of the top 10 this year meet that criteria!
Lowering barriers to contributions is great but I don't buy this "vendors are talent vacuums" mindset.

Of the top 10 contributors this year:
* 2 moved companies and increased contributions
* 1 left for an unrelated role
* 4 are new contributors
* 3 have no changes

All but 1 are employed by Istio vendors (the other is an
end user).

I assume the implication is they are taking them away from OSS to work on closed source things -- in the 6 years I've worked on Istio I cannot recall a single time this has happened. My contributions doubled the moment I moved!

I've never really understood why vendors are seen as this "villain". They are ruining OSS by... investing millions of dollars into paying maintainers to work on open source?