Twitter Bootstrap has been around for almost two years and has made quite an impact on how developers see UI development. Before Bootstrap was introduced, I've seen a few tool-sets on the Web being used, but each had flaws and most of the times implementing them in projects used to give developers quite a headache. The most important problem was cross browser disparity. Twitter Bootstrap pretty much covered equality of UI design rendered through most browsers. Even in Internet Explorer. This really was a really big achievement. Putting that aside, the fact is that in these 20 months or so, many web sites with a Bootstrap based theme have been launched. These websites were really well accepted on the Web. Also, developers loved it because it was much simpler to make extensions.
Designers, on the other hand hated it, because they couldn't work outside of the box, because everything is pretty much boxed up and the limitations ware, I suppose, very frustrating. But, as a developer myself, I must say that development of Administrator dashboards and CMSs for websites I've worked on, Bootstrap was and still is a real saviour.
However, all good things eventually come to an end, and I think that Bootstrap will not avoid this fate. Do not “read me wrong”. I like Bootstrap a lot, but I see many “front-ends” being developed with Twitter Bootstrap as the core and although one CAN make changes and customize CSS to keep only the functional layout workings, responsive helpers and certain useful block styling from the core, most people do not bother doing this. They just make small changes such as logo change, colour changes (sometimes), maybe an icon set change (rarely) and this is why there are thousands of websites and blogs out there that look exactly the same.
People grow tired of seeing the same “old” boring look and design and they constantly search for something new, inspiring, challenging, different, etc. When I stumble upon a website that obviously uses Bootstrap as its front end’s core, I really get agitated.
I see now that Twitter Bootstrap has two possible fates. One is to completely die out as a core tool-set for website development. This is if it continues to be used for front ends. The second is that it remains the favourite behind the scenes dashboard and CMS styling tool, because unlike our fellow colleagues - designers, we developers just can’t make the UI look good, and for CMSs, we don’t really feel it necessary. This is why I believe that, if it does not completely dies out, Bootstrap will still be used there where most Web users won’t see it.