It sounds like there is a lot of work happening on sparse networks now, so it’ll be interesting to see how this changes in the near future.
I'm not saying it's impossible but if resources allow it makes a lot of sense to start with the biggest model you can still train. Especially since for whatever reason things seem to get a lot easier if you simply throw more computing power at it (kind of like how no matter how advanced your caching algorithm it's not going to be more than 2 times faster than the simplest LRU algorithm with double the amount of cache).
There has been a lot of work on sparsity and discovering sparse subnetworks in trained dense networks. And intel even proposed some alternative cpu friendly architectures and torch/tf and gpus are starting to do okay with sparse matrixes so thing are changing.