There is a pretty good reasons why shopping local is better in the long run:
The money you put in stays local in large parts or entirely and keeps the comminuty alive, paying peoples jobs, who in turn pay other people once they buy local.
Large companies siphon the communities wealth away until there is nothing left, before closing shop and running of to the next victim, leaving empoverisht people behind.
The effect is compounding. The more local shops close, the more other jobs dissappear and the less people have. Then they are forced to move away or buy less in general. Other firms cant hold their workers and have to cut down wages, or let people go due to reduced business operstion because no one can afford their services, continuing the spiral.
At the end of that process, all you will find are dollar-stores and junkfood-chains in your area. It happened a few times already and the effect is well understood.
TLDR: Shopping local is good for the community, buying everything online is siphoning money away from it instead.