It's absolutely not the case. It's more like a conspiracy theory that keeps getting pushed into Bitcoin-related threads at Hacker news (maybe to tilt future analysis?)
If we take a look at the past month of commits from https://github.com/bitcoin/bitcoin/pulse/monthly, the top ten authors are:
- MarcoFalke
- fanquake
- hebasto
- ajtowns
- glozow
- ismaelsaadeq
- TheCharlatan
- instagibbs
- brunoerg
- mzumsande
None of them works at Blockstream.
When you say "long ago", it likely points to the "Bitcoin Cash" incident. Almost every person that knows of Bitcoin Cash thinks that Bitcoin is a scam; almost everyone else laughs at the idea of Bitcoin Cash working.
Long ago, that was also the case: https://old.reddit.com/r/Bitcoin/comments/61blfg/blockstream...
(edited for format)
(I am the longest serving engineer at Blockstream).
Bitcoin Core, long ago, was "purchased" by Blockstream and they started pushing their own agenda for the protocol, and Luke Jr is one of the devs on their payroll.
Yes, of course, you can create your own wallet or node but unless 51% of the network uses it, your protocol changes will never reach the whole network.