There are issues with this in the USA.
First a business does not want any unauthorized access from outside phones laptops. It's a recipe for disaster with virus's and potential access to sensitive information.
All communications from and to the company you want to monitor for reasons like what are people actually using the devices for and how do they deal with customers.
Big important part here is **** viewing and child ****. You can't have a hostile work place to other people. i.e. a male watching **** and upsetting female employees. Child **** or similar has to be watched for as it is a business allowing employees to do this. Imaging the negative publicity for the firm if they caught the person. Better to have company equipment standardized and monitored.

It is almost "trivial" (for someone with good HTML5 coding skills) to create a interoffice intranet/'virtual private network' (as opposed to the internet) where all information stayed on the server and was displayed but not downloaded, and that even provided access to diagnostic programs, with some configuration of the local devices (and with some 'latency', due to -not- universal high speed wireless access, no one wants to wait for anything).
I kind of get the feeling that what is preventing this is more what Raytech points out; "profit margins", {and who gets the profit from doing the work,} than the technology. I think there are still a lot of dealer principals who are having 'sticker shock' at the cost of having an IT department and all the laptops and phones they purchased in the last 15 years [even if most of it went for the sales department], and would not want to consider any added expense that was not easily passed on to a customer.
Europe, Asia, South America and Africa will be better equipped to adopt that tech (than North America, not sure about "downunder's" mobile phone access), as their mobile phone access systems are actually competitive and offer better access speed and not quite as monopolistic as the systems in North America.

In this local market, I know the Yale dealer makes/helps the tech purchase their own laptop, and installs the proprietary software for them. The Hyster dealer provides a company laptop, and has published rules that allow no personal use of that laptop, and controls access when on corporate networks to only "trusted sources". Last I knew, the Cat/Mitsu dealer was very flexible and had mixed BYOD and company provided devices both for phones and laptops. The company I work for is trying to get everyone to use their own 'smart phone' and they pay only for the 'cloud access' to programs that the company uses. I feel this is very much a 2 edge sword, as the customer may get used to calling the tech, and the tech may take that customer with them. just as they will take their phone, when they leave the company.

I kind of think these things are changing so quickly that whatever is the standard today, will be like beepers. (obsolete and only a memory in 20 years or less).
A lot of these changes have been waiting for more ubiquitous adoption of the IPV6 name/number system than any other bottleneck, and that is starting to 'come on strong' these days.
My apologies if I come on a little more nerdy than usual, both industrial trucks and computer tech are my personal passions/interests.

I think it may evolve to to that. Market share is dropping, competition is fierce and bottom line is may dictate employers to go that way. I can see us losing most of our perks soon as our door rates are lower now than years back. Many tech's destroy their company laptops or Ipads from carelessness. It will be replaced at no-charge to them. Most techs are abusing cell phone data by watching You-Tube or streaming videos. We have a company APP within our phones that shows our employer every key stroke we make, but tech's still abuse it. The company does track our every move with their supplied phones, and has software in laptops and I-Pads that "tells" them if we share info.
It's that proprietary info that would be an issue with personal laptops. the company would have no control of that info and could lose sensitive data on customers. There would be no controls in place, no security. Our company I-pads are linked directly to their server. If you try to access internet, it goes on wi-fi only and wont let you do any company business.
There is no single scan tool to use on lifts, like OBD2 on all cars, so it can get pricy for a tech with no access to most trucks