I think that BTC was in a bubble in 2017, but that is almost nothing compared to new bubbles which will come in next few years. BTC is nothing like tulip mania, because tulip bubble burst only once and never came back.
Tulip mania doesn't have anything to get relative to the bitcoin. What we see with bitcoin is the real growth, at times there were little price manipulation and the same gets termed as bubbles if it provides with a large scale profiting. Growth waves will continue to be a part of cryptocurrency, and this at times gets mentioned as bubbles. Nothing is gonna happen on these indications.
Unlike money circulating programs, bitcoin got many real-life applications which makes it worth to invest hence bitcoin cannot be a bubble. It is gaining value for its utility and usage for real-life needs. Sometimes, bitcoin prices may get pumped to beyond the demand levels and then it might get burst out. That is common for any commodity. If bitcoin is a bubble then gold is a also a bubble because gold also has nothing different from bitcoins. Gold is a just a metal and only due to demands its gaining its value whereas bitcoin is a digital asset and lives only in electronic format and this also gaining its value exact similar to gold.