I see your points. As a [freelance] Consultant, my resume has over 40 over-lapping, yet relatively short duration (2-6 months) positions listed. As a Farm/Server Architect and Admin for very specific technologies like SharePoint Server, MS Project Server, O365 SharePoint Online/Project Online, I typically Architect the server farm(s), install and configure the servers (automated as much as possible) and turn over the keys. Every day a recruiter calls or a client questions me about the short durations, I simply say "How long did you keep your Architect around after your house was built?" Very few companies need a relatively expensive Architect full-time...which suits me because I've had exposure to so many problem sets, environments, company cultures, great people [mostly].
At many companies I meet some IT folks that have worked at their company for 15+ years. They are typically the ones that need the most help as they have mostly only had exposure to their problem sets and methodologies. New tech, in some cases, scares the heck out of them. The younger ones seem more eager for the change(s)...but c'est la vie.
On one version. I also have a standard one-pager, a 6-pager, and a 12-pager resume for those HR/recruiters looking for depth + breadth experience. Per one 'job board', I actually get about 30% more contracts from my 12-pager than the other two versions combined: keywords and keyword density I am sure.
I have a 2-pager "Contracts" list that just lists companies, dates, position, and a 1-2 sentence blurb about each...and this is just for SharePoint/MS Project/O365 contracts since 2008...not even my whole career, nor oddball stuff [Adobe LiveCycle Rights Management Config: WTF?, Clarity PM Development, custom map software, etc.], nor short <30 day issues if the client wasn't "notable".
I have seen other Consultants with significantly more experience than me that have multiple pages just for publications, books, courses taught, etc. and/or patents on their resume. Due to the enterprise market that SharePoint once exclusively targeted, most of my clients are large Fortune 500/1000 companies and listing the numerous ones I have worked with has not been a noticeable, or even real, detriment.
My line of thought: "Would $hiringManager hire someone that only worked at 2 or 3 places [no gaps though!] to solve this problem, or would $hiringManager hire the consultant that has blasted problems away at over 40 notable companies, wrote/taught courses on x, wrote the book on x, etc." My gaps are [invisibly: not listed] filled with 'smaller' work/contracts, that if listed, would multiply my resume's page count by some factor of ridiculous and, to some uninitiated, dilute my value. First world problems.
I do see that Architect/Administrator work for on-premise SharePoint/Project is declining while more SMBs are buying into Office 365/SharePoint Online/Project Online. Yet, just today, no less than 3 contracts/RFQs came in for on-prem SP2013 to SP2016 migrations. One contract I cannot take because it is in NYC and for a City government migration (not top fees and typically difficult to work with, and too far away); a largish Seattle company (~7B revenue FY15) that is qualified and has an interesting business and requirements; and a consulting company in Hollywood that needs someone 'yesterday' to fix/correct workflows in their large studio client's workflow manager farm prior to the SP2016 migration.
At many companies I meet some IT folks that have worked at their company for 15+ years. They are typically the ones that need the most help as they have mostly only had exposure to their problem sets and methodologies. New tech, in some cases, scares the heck out of them. The younger ones seem more eager for the change(s)...but c'est la vie.