I don't think it had any plot driven change.
The Bond franchise was feeling threatened by newer spy movies (such as the Bourne series) which have more action, (slightly) more plausible plots (compared to ray-gun satellites etc), and have less comedic elements.
A reboot with a new younger actor and a deliberate step away from some of the conventions of the franchise (gadgets & moneypenny for example) were their answer.
They tried to take it this direction before - a Licence to Kill was a deliberate attempt with a drug-smuggling and revenge plot-line, but wasn't well done.
They then decided to switch back to more 'classic'
Bond approaches with Brosnan.
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Love the other answers already given but one extra contributory factor may be that, and you may not remember this, there was a huge backlash against 'Die Another Day's over-use of frankly bullshit technology and the makers commented at the time that they knew they'd gone too far.
In particular the invisible car was just laughed at when I saw it theatrically, as was the huge laser that could destroy land targets but seemed to only warm up the plane gradually, plus the ice-hotel, the VR headset and a number of other items that not only didn't add anything but actually made the film laughable.
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The new movies starring Daniel Craig were intended as a reboot of the series.
As part of that reboot it seems that they have moved away from having so many gadgets and are focusing more on the character's own abilities.
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After seeing the preview to the new movie Skyfall, I think there might be another possible explanation.
In the preview, they introduce Q for the first time in the reboot.
They also seem to imply that Q is going to "revitalize" MI6, maybe with more emphasis on tech support instead of purely physical methods of getting information (as Daniel Craig has done in the earlier movies).
Perhaps there are not as many gadgets because this reboot emphasizes the beginning of 007 and is before Q is there to create the gadgets.
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I don't think Bond is less "tech savvy" in the new Bond films.
It is a definite move away from the Moore/Brosnan era.
The new approach to the character is less tech driven and moves more toward the literary character.
Although the Bourne films can be credited for the more gritty fight scenes and slick editing, you only have to look back at From Russia with Love and On Her Majesty's Secret Service for early examples of this style of Bond.
Both of these Bond films were credited to be nearer the literary character than any other and were also very low tech in comparison to other movies.
It would seem that the Daniel Craig Bond is a step in this direction which (for me) is a very good thing.
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It could be due to the now wider spread knowledge of technology.
People are more educated about science and technology now and would be less willing to forget or believe any of these technical feats.
Instinctively they reject them.
It's laughable for a person such as James Bond to know so much about gadgets and technology which would make anyone who is a little tech-savvy laugh and mock what's been done in previous movies of the franscise
(eg think about Roger Moore disarming a nuclear bomb in 'The Spy who Loved Me' and never even sweats!, or the bond-turned-star-wars in 'Die Another Day', or I can think of at least 8 other laughable occassions).
I find the approach that started with Daniel Craig definitely more realistic.
Daniel Craig's Bond is not a superhuman, he's grounded, he's in pain
, he hurts, he doesn't have an answer and a joke for everything and as such the audience can sympathize with him.
Other spy movies like Bourne (which was better than almost all Bond movies at the time) or Mission Impossible influenced this turn of the tide.
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The most recent installments of  James Bond  (ones featuring Daniel Craig) have fewer gadgets but more raw action (like the chase sequences in Casino Royale and Quantum of Solace). Is it because of plot related changes to the MI:6 or have the movies been altered to suit the audiences?
Why is James Bond less tech savvy in the Daniel Craig movies?
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It could be due to the now wider spread knowledge of technology.People are more educated about science and technology now and would be less willing to forget or believe any of these technical feats. People are more educated about science and technology now and would be less willing to forget or believe any of these technical feats.
Invisible car, huge laser, VR headset and ice-hotel among items that made film laughable. Inventive car was just laughed at when I saw it theatrically, says reviewer. People are more educated about science and technology now and would be less willing to forget or believe any of these technical feats.