https://www.forbes.com/sites/forbestechcouncil/2018/04/19/in...
https://www.forbes.com/sites/forbestechcouncil/2018/04/19/in...
The Computerphile YouTube channel as some interviews with computer scientists that worked at Bell Labs during their heyday. It's incredibly interesting to hear about how they screwed around with early Linotype printers (which $100k+ in the 70s) and did things like reverse-engineer the font formats to create custom chess fonts.
They had direct-dial long-distance by 1951, using relays and tubes.
The transistor started making a difference in telephony with the release of the 1ESS switch in 1965. But transistors were a commodity by then.
As you say, bigger companies have a harder time innovting.
Of course, if you are bigger, the more likely it is that there is no competition at certain times.
If you can survive without investing, a lot of companies choose not to.
Microsoft / IBM and now Intel defintely did.
I think it has more to do with the leadership of the company than the size of the company.
-ss