Type size won't change in Digital Editions for many ebooks

I have found that for many ebooks the type size in Digital Editons will not change. The methods given by Adobe to change it do not work.

I know this is an ancient problem. Complaints about it go back at least 11 years, suggesting that it is a software deficiency Adobe is not going to address.

Anyone know any tricks to get around it? (Aside from switching to Kindle?)

Thanks,

DC