Sounds like your 32-bit OpenGL driver install got killed by your update? You can try installing mesa-utils:i386 and re-running that glxinfo command to see if it works properly.

Thanks for your response, however, installing mesa-utils:i386 (and rebooting) did not make any difference:

$ steam
Running Steam on ubuntu 16.04 64-bit
STEAM_RUNTIME is enabled automatically
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
grep: symbol lookup error: grep: undefined symbol: pcre_jit_stack_alloc
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Gtk-Message: Failed to load module "gail"
Gtk-Message: Failed to load module "atk-bridge"
Gtk-Message: Failed to load module "unity-gtk-module"
Installing breakpad exception handler for appid(steam)/version(1454620878)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
[0214/110102:ERROR:main_delegate.cc(777)] Could not load cef_extensions.pak
[0214/110102:ERROR:browser_main_loop.cc(203)] Running without the SUID sandbox! See https://code.google.com/p/chromium/wiki/LinuxSUIDSandboxDevelopment for more information on developing with the sandbox on.
Installing breakpad exception handler for appid(steamwebhelper)/version(20160204122139)
Installing breakpad exception handler for appid(steamwebhelper)/version(1454588499)
[0214/110102:ERROR:main_delegate.cc(777)] Could not load cef_extensions.pak
Installing breakpad exception handler for appid(steamwebhelper)/version(20160204122139)
Installing breakpad exception handler for appid(steamwebhelper)/version(1454620878)
Installing breakpad exception handler for appid(steamwebhelper)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
Created shared memory when not owner SteamController_Shared_mem
Installing breakpad exception handler for appid(steam)/version(1454620878)
Installing breakpad exception handler for appid(steam)/version(1454620878)
surface_opengl.cpp (594) : Assertion Failed: id
Assert( Assertion Failed: id ):surface_opengl.cpp:594

Installing breakpad exception handler for appid(steam)/version(1454620878)
crash_20160214110102_14.dmp[2758]: Uploading dump (out-of-process)
/tmp/dumps/crash_20160214110102_14.dmp
assert_20160214110100_1.dmp[2761]: Uploading dump (out-of-process)
/tmp/dumps/assert_20160214110100_1.dmp
/home/rojaro/.local/share/Steam/steam.sh: line 756:  2700 Segmentation fault      $STEAM_DEBUGGER "$STEAMROOT/$STEAMEXEPATH" "$@"
crash_20160214110102_14.dmp[2758]: Finished uploading minidump (out-of-process): success = yes
crash_20160214110102_14.dmp[2758]: response: CrashID=bp-584cbccc-e55c-4866-b023-6d3e12160214
crash_20160214110102_14.dmp[2758]: file ''/tmp/dumps/crash_20160214110102_14.dmp'', upload yes: ''CrashID=bp-584cbccc-e55c-4866-b023-6d3e12160214''
assert_20160214110100_1.dmp[2761]: Finished uploading minidump (out-of-process): success = yes
assert_20160214110100_1.dmp[2761]: response: CrashID=bp-58569513-9e83-43aa-9b9b-dbbb82160214
assert_20160214110100_1.dmp[2761]: file ''/tmp/dumps/assert_20160214110100_1.dmp'', upload yes: ''CrashID=bp-58569513-9e83-43aa-9b9b-dbbb82160214''

$ glxinfo | grep version
server glx version string: 1.4
client glx version string: 1.4
GLX version: 1.4
OpenGL core profile version string: 4.5.0 NVIDIA 361.28
OpenGL core profile shading language version string: 4.50 NVIDIA
OpenGL version string: 4.5.0 NVIDIA 361.28
OpenGL shading language version string: 4.50 NVIDIA
OpenGL ES profile version string: OpenGL ES 3.2 NVIDIA 361.28
OpenGL ES profile shading language version string: OpenGL ES GLSL ES 3.20
    GL_EXT_shader_implicit_conversions, GL_EXT_shader_integer_mix, 

$ dpkg -l | grep mesa-utils
ii  mesa-utils:i386                                             8.3.0-1                                    i386         Miscellaneous Mesa GL utilities

I have the same problem. I'm running Ubuntu 14.04.3 64 bit and just installed the newest NVidia drivers 361.28. I found the solution in the Arch Wiki:

__GLVND_DISALLOW_PATCHING=1 steam

Seems to work so far. But either the drivers for Linux are bad, or something else is wrong, because I can't even play INK without lag :(

where d you apply __GLVND_DISALLOW_PATCHING=1 steam?

This is the command you run from the command line.

oh ok thx

Closing this issue as i can no longer reproduce it and the problem went away for me.