Whilst I understand the comments from PPs (who are mostly child-free, I think), the comment I've taken on board the most is the one saying but these are family events and your child is FAMILY. I think this is key, as families do evolve and change.
And I also agree with those PPs who've said things might change again once other people start having children (although i note the OPs comment that there do seem to be other DC, but they may be older).
I do think toddlers will change and evolve, although it partly depends on the child. Some ages and stages can't cope with flexibility and others cope with it much better. And also depends on your childrearing decisions (eg how flexible your routines are), so I would expect things to change as your child changes and grows.
But this reminds me that my mum always moans this was like that for her when me and my DSis were younger - no accommodation made and it made life tough for her. And family members would openly eye roll if we were tired/hungry/bored and therefore not behaving our best. I was never aware of this, but my mum was and resented it at the time and STILL carries this historical resentment with her, even though I'm nearly 50! So, for example my younger cousins who now have DC of their own are accommodated for Christmas, etc and mum will mutter to me that she never was.
However, now I'm on MN, I can see that my mum's problem/issue was actually a DH problem. HE should have supported her. HE should have stepped in more. HE should have taken on more of the childcare at these events. And, most key, he should have spoken to his family on my mum's behalf.
But he never did.