So, after the investigation, I am going to answer my question with a few statistics that I was looking for:
No known active tablets or mobile phones use IE8, as far as I can tell. Event: The earliest Windows phones use the IE9 engine. Thus, laptops are excluded, IE8 is not used by smart mobile devices.
According to w3counter, statcounter, and analytics from 3 client sites, the IE8 browser share in March 2013, based on US sites, ranged from 5% to 11%. The average value is 8%.
The number of IE8 users using screen resolutions of 800x600 pixels or less today, according to three different sites that I studied in the USA, ranges from 0.6% to 1% of the total IE8 user base. Following the trends observed last year by Jacob Nielsen, “small screens for desktops and laptops are becoming rare”, fall to 1%: http://www.nngroup.com/articles/computer-screens-getting-bigger/ p>
Today, this leads to the average expectation that common IE8 users with a screen size of 800x600 or less are approximately 0.05%, a maximum of 0.1% if we enable IE7; lower than US IE6 total usage, accounting for 0.2% according to ie6countdown.com
Thus, the flexible design compatibility requirement below IE9 for IE7 and IE8 users is well worth the effort.
If you enable polyfill media queries or use Bootstrap, it works right away and then fine. But it definitely doesn’t cost more than a few hours to deal with numerous potential errors (a Google search for “bootstrap ie8” says that), since it no longer makes websites completely compatible with IE6.
While the site works in IE8 with a fixed design, which may be easier to implement, rather than trying to painfully make it respond to IE8 / IE7, this is enough for today.