lots of small companies are reliant on the cheap prices big tech companies offer. by taxing big companies all that does is shift the burden of costs to the small business, making it harder for them to grow.
The race to the bottom in terms of pricing is destroying a lot of value in many industries and in the longer term is harmful to everyone who isn't already a big company.
People and small companies kicking that addiction will be painful, yes, but important to everyone having a healthier life.