It seems excessive, but I've seen some weird shit.
I recently did some work for a company that had BOTH Office365 and a six server Exchange on premise system for maybe 500 users. Not a hybrid deployment, but two separate systems with some crazy SMTP smarthost configuration to make it act more like a hybrid configuration. Worse, the on-premise setup was a 2010/2013 hybrid with a mishmash of CAS- and mailbox-only servers and combined roles.
This same company had 30 VMs to support a single application. I didn't have anything to do with that "system" but I had a hard time wrapping my brain around how that was meant to work. Not surprisingly, this company had been a mostly-outsourced IT shop for years.
10 plus years ago I worked in advertising and that was just a plain crazy business. Client business was often based in a specific agency office and each office expected to be able to run as independently as possible and given the account management and business goals and incentives, most offices had the juice to see it done that way. One office in Irvine had (in 2001!) nearly 800 GB of storage over four servers for a headcount of less than 30. Such setups were the norm, not the exception in the 4 local offices I oversaw.
The business structure abetted this -- our agency was run as a standalone company, but wholly owned by an international holding company dominated by about 4-5 major players. Most smaller agencies had management and reporting through one of the majors, and this led to all kinds of crazy attempts at consolidation of vendors, back end services and often competing cloud-like initiatives -- two of the majors had their own private cloud-like initiatives AND there was a separate, holding-company wide initiative (mostly backed by the 3 smaller majors) that overlapped with the individual ones. From what the CFO told me, while these initiatives made some sense from elimination of redundancy the biggest motivation was the juicy "management fees" that hit the revenue side of the books of the entity controlling the initiatives. We paid $100k/year in "IT management fees" to our reporting major for literally nothing other than changing large Dell PC orders behind our backs to meet their standards (shipment refused at the dock).
It was compounded by the holding company's habit of occasionally stripping a remote office from one agency and relabeling it as another agency's office to make some client at the new parent's office with a geographically local office in the remote office's city happy they had a "local office". You can only imagine the IT chaos this led to and usually the net result was that individual office locations mostly ended up being their own IT islands just to get the job done versus frequent rip-and-replace restructuring to integrate. A small agency in San Diego got turned into one of our offices and I had two senior management officials call me within a half an hour with totally conflicting directions. The head of creative was demanding maximum integration, as soon as possible, and the CFO told me not to do a damn thing but be nice as financially we would be spending $0.00 on any integration tasks along with a Godfather-like reminder of "who I reported to."
Anyway, it's not hard to see how IT can turn into a runaway train if you combine strange business structures and incentives with outsourcing.