Politics will NEVER implement something that most people are against - so yeah it's 100% on individual responsibility to change first and show them that it's no problem if meat or flying or even fuel gets much more expensive since it's not sustainable at this level since they already reduced their consumption.
If people don't do that first then politicians won't take those measures.
Just see what the (small) rise in gas prices for the end-user from Russia attacking Ukraine did in terms of protests and people blaming politicians on being responsible for the high prices.
Also if you vote with your wallet then there is incentive for the big corporations to change, too (even if that alone won't solve anything it's still helping). For example the biggest producer or meat replacements in Germany is a really old company that only sold meat until a couple of years ago.
They started some test balloons and because people kept buying it they kept increasing the production amounts and now they sell more replacement than meat.